Retsu Unohana

Retsu Unohana (卯ノ花 烈) formerly originally known as Yachiru Unohana (卯ノ花八千流), was the first captain of the Fourth Division in the Gotei 13. She was one of the oldest, and most experienced captains. Retsu was also the Soul Society's best healer, as well as the first person to wield the name Kenpachi. She also formerly served as the Captain of the 11th Division. Her lieutenant was Isane Kotetsu who succeeded her as the captain in a later date.

Background
She was born on the day of April 21st. At some point in the past, she had named herself Yachiru Unohana, and was known as the most diabolical criminal to ever exist in all of the Soul Society. Genryusai Shigekuni Yamamoto sought her out and she joined him, becoming one of the founding members of the Gotei 13. Unohana laid the foundations of what would be known as the 11th Division and became its first captain, as well as the first Kenpachi. At some point in the past, Unohana was taught medical techniques by Tenjiro Kirinji as a way of prolonging her future fights.

Some time later after becoming a captain, she undertook a mission to eliminate the warriors on the edges of Rukongai. Having lost interest in fighting altogether, Unohana wandered from place to place in search of something that would please her sword, and came across a young boy who would one day be known as Kenpachi Zaraki. Attacking her on sight, the boy was able to injure her, causing the woman to once again enjoy fighting. However, despite being the one left standing at the conclusion of their battle, she realized he was stronger and was better suited to become Kenpachi.

Some time after this fight, Unohana left the 11th division and became captain of the 4th Division. She has been one the Gotei 13's longest tenured captains alongside fellow captains Yamamoto, Jushiro Ukitake and Shunsui Kyoraku. Ukitake also refers to her as "Senpai", denoting her seniority to both him and Shunsui.

Approximately 110 years ago, Unohana was present for a promotion ceremony that took place at the 1st Division Headquarters, along with the rest of the assembled captains. She witnessed the arrival of the newly appointed Captain of the 12th Division, Kisuke Urahara. Her lieutenant at this time was Seinosuke Yamada.

9 years later, Unohana was present at a emergency meeting called by Captain-Commander Yamamoto where he decided to create a investigation team to locate the missing 9th Division members. When he gave out orders, Yamamoto ordered Unohana to prepare the relief stations for casualties, but she interrupted him, and asked if it wouldn't be better for her to tend to the wounded there. Yamamoto plainly told her that he couldn't send healers out without knowing what the situation was like.

Unohana was present when Isshin Kurosaki made his report about the mysterious Hollow known as White.

Personality
Unohana has a gentle, and warm personality that augments her appearance. Unohana is a soft spoken, polite, and caring woman who uses honorifics when addressing everyone, including her subordinates and the enemy. She rarely shows any signs of panic or distress, and has a great sense of duty, shown in the times that she orders Hanataro Yamada's imprisonment and Isane Kotetsu’s chasing of Renji Abarai when he runs away with Rukia Kuchiki. Despite her sense of duty, she will also heal almost anybody around her, including Renji after he was defeated by his captain, Gantenbainne Mosqueda when she arrived in Hueco Mundo, and the Visored, referring to them as allies despite Shinji's reluctance to do so. With her grace and kind manners, she lets others know quietly that while she may be soft, she is not to be taken lightly. Despite her gentle nature, several members of the Eleventh Division and even her fellow Captains fear her.

However, after the revelation of her past as the first Kenpachi and Shunsui Kyoraku calling on her to draw on her experience from then, Unohana's personality has taken a much darker turn. Remaining ominously silent during the meeting with the Central 46, it isn't until her fight with the current Kenpachi that she shows her original violent and bloodthirsty nature, commenting how the scar left on her chest was causing her pain just from the sound of the latter's voice. Unohana herself says that she is infatuated with crossing blades.

Unohana likes strong flavored food, preferring it to bland tasting dishes. In her free time, she climbs mountains throughout Rukongai; during these excursions, she collects medicinal herbs. Once a month, she holds an ikebana class for the members of her division and she is also the President of the Ikebana Club.

Appearance
Unohana has the appearance of a slender, and very youthful woman with blue eyes and black hair. She wears the standard Shinigami captain uniform apart from using an obi instead of the normal sash. Her hair is long and is always worn as a large braid down the front of her body. Over 100 years ago, she did not have the large braid, instead styling in front of her as a loose ponytail. While maintaining a kind and gentle look at most times, during her battle with Kenpachi Zaraki, her eyes appear gloomy and very menacing. She also wears her hair down for the first time, and is revealed to have been covering a notable scar in-between her collarbone, inflicted by Kenpachi when the latter was young. Before Kenpachi inflicted said scar on her, she did not tie her hair in front of her, instead wearing it down at all times.

Unlike most Shinigami who carry their Zanpakuto in their sash, Unohana has a large string attached to the sheath of her Zanpakuto and carries it over her shoulder, or has her lieutenant, Isane Kotetsu, carry it for her whenever they are together on the battlefield.

Master Healer
She learned the healing techniques that she currently uses from the Royal Guard Tenjiro Kirinji. Though she originally learned healing Kido as a way to prolong her fights, Unohana has become the most knowledgeable on health related matters in all of the Soul Society. She is known to be highly proficient in conventional healing techniques and herbal healing. Her knowledge of anatomy is great enough that upon examination of Aizen's "dead body", she concluded it was not Aizen or even real. She is also able to heal more than just Shinigami, as shown when she heals Yasutora "Chad" Sado, a Human, as well as Gantenbainne Mosqueda, an Arrancar.

Kido Master
As one of the oldest and most experienced captains, Unohana has advanced knowledge of Kido and the flow of spiritual energy. Her knowledge and mastery of healing Kido are unrivaled within Soul Society. Unohana is well-versed in a variety of Kido, highly masterful in healing Kido, and is able to easily use high-level Hado and Bakudo spells without incantation.

Immense Spiritual Power
As one of the oldest Captains in the Gotei 13 and therefore one of the most experienced, as well as being one of its most powerful combatants, Unohana has a tremendous amount of spiritual power. Unohana has pointed out that Kenpachi Zaraki's power rivaled her own (even as a child), though she herself was weaker than him. Therefore she acknowledges that she is stronger than everyone but him.

Master Swordsman
Unohana's personal specialty is sword fighting, particularly her mastery in the art of Kendo. She is said to know all 8,000 of the world's schools of swordsmanship, as well as all the swords, hence the meaning behind her previous name, "Yachiru". Her skill level in swordsmanship is far superior to even the combat oriented 11th Division captain, Kenpachi Zaraki, as she is able to easily best him for a considerable amount of their fight after centuries of not engaging in melee combat. She also has a combat philosophy that allows her to use any means necessary — even tricks such as hidden daggers — to gain the upper hand in a fight.

Shunpo Expert
Unohana is proficient enough in this skill to be as fast as the average captain.

Hakuda Combatant
During her fight to the death against Kenpachi Zaraki, she was proficient enough in Hakuda to deflect his sword swing using the back of her free hand to create openings for attacks, and could also use her leg to block Zaraki's sword hand mid-swing to prevent it hitting her and leave him exposed at the same time.

Keen Intellect
Along with her general skill of healing, she is able to detect the smallest details in her patients. This aids her in her healing. She can detect anomalies and problems lesser healers would not. She can tell by a simple look what type of medical attention, if any, is needed. She is also a keen analyst with great attention to detail, able to quickly determine how to counteract any ailments a person may have. Her powers of perception were great to deduce that Aizen's elaborate illusion of a corpse doll wasn't real, and that Aizen was perpetuating a much larger scheme.

Minazuki
Minazuki (肉雫唼, "Flesh-Drops' Gorge"): In sealed form, Minazuki is slightly longer than an ordinary katana, and resembles a nodachi. The tsuba has an oval shape, and the handle is red. Instead of tying it to her obi, Unohana carries her Zanpakuto over her shoulder by a rope strap, or lets Isane carry it for her.

Shikai
Its release command is unknown. When released in Shikai form, Minazuki will start to morph, turning into a green, gas-like substance before taking the solid shape of a giant, green, one eyed manta ray-like creature with the ability to fly. Minazuki can be used for transportation, and will change back into the green gas substance before returning to its sword form when its duty has been fulfilled.

Shikai Special Ability
It is large enough to transport many people on its back (at least a dozen, based on its size when compared to those riding it). It seems to act on verbal orders, and when landing it has the ability to somehow create a pair of bird like legs. Minazuki's main aspect is its ability to heal. When the wounded are placed within Minazuki's mouth, they are swallowed and stored inside its stomach. Minazuki's stomach acids are strong healing medicines and ointments which gradually soak over the wounded, curing their injuries. Currently, it has shown the ability to carry at least six people within its stomach. When Unohana gives the word, Minazuki will regurgitate the people back out of its mouth.

Bankai
Minazuki (皆尽, "All Things' End"): When released the blade of Unohana's Zanpakuto liquifies into a thick, dark red substance able to surround her vicinity. Once the majority of the liquid flows off the Zanpakuto, it reveals the remainder has solidified into a shortened katana, which then can be used for combat, strong and sturdy enough to clash against Kenpachi Zaraki's blade.

Bankai Special Ability
Unknown.

Soul Society arc
Retsu Unohana attends a captain's emergency meeting called by Captain-Commander Yamamoto. However she says nothing at this time and remains silent throughout the bickering between her fellow officers. After Sosuke Aizen's apparent death, she exams the body and confirms to Sajin Komamura and Kaname Tosen that he is truly dead. When Hanataro Yamada is brought before her by the 13th Division after aiding an enemy, she determines that Hanataro must be imprisoned on account of the fact that he is a Seated Officer in her Division and may have accidentally aided in the harm that the Ryoka had supposedly done within Seireitei.

While attending the execution, Isane Kotetsu expresses open regret that Yamamoto lied to Rukia regarding the release of the Ryoka, but Unohana explains to her lieutenant that despite the harshness of such a lie, it also allows Rukia to die peacefully with the idea that her friends' lives would be spared. After Ichigo Kurosaki arrives on the scene and destroys the Sokyoku stand, Sui-Feng orders all lieutenants to follow the fleeing Renji and Rukia. Isane, concerned about the order, looks at Unohana, and the latter calmly tells her to go, only to see the former lose to Ichigo.

After defeating the lieutenants, Ichigo starts his battle with Byakuya Kuchiki while the captains then head off to their respective battles. Unohana releases Minazuki, even though the actual process is not shown, and saves all those hurt during the initial battle. She keeps Isane with her on top of Minazuki while her Zanpakuto heals the rest of her patients inside of its stomach. Arriving at the Relief Station, Unohana asks Minazuki to release everyone, and seals it back while calling for her subordinates to tend to the injured personnel for the time being. She then asks Isane to follow her to the Central 46 Chambers.

They arrive at the scene in time to see Aizen defeat Toshiro Hitsugaya. Captain Unohana announces her presence to the traitors while citing her own suspicions surrounding Aizen's staged death. She also goes on to claim that the residence area in Central 46 Compound was the only place he could hide and mentions the use of an elaborate corpse doll on his part. Aizen then points out the mistakes in her analysis, while also commending her for seeing through his deception. The first was that he was not here to hide, and the second was immediately shown as he releases his Zanpakuto in front of Unohana and explains Kyoka Suigetsu's Complete Hypnosis.

He then proceeds to tell Unohana about the third member of his group, Kaname Tosen. He and Gin Ichimaru then teleport to Sokyoku Hill, leaving them behind. Unohana immediately requests Isane to find out his exact location and inform everyone of Aizen's betrayal, including the Ryoka. She then takes steps to heal Hitsugaya and Momo Hinamori, both who were fatally injured by Aizen before her arrival.

After ensuring that both would escape death for the moment, she leaves them in the care of Isane and travels via Minazuki to the Sokyoku stand, where she tells Yasochika Iemura, the 3rd Seat of her division, that the Ryoka do not require help. She then settles down beside Byakuya and gently scolds him, saying that he has pushed himself too hard. She then calls Rukia over upon Byakuya's request, during which he reveals his reason for allowing her execution.

A week after Aizen's insurgency, Unohana stops two 11th Division members from creating a ruckus at the 4th Division’s Relief Station, and unsuccessfully tries to convince Hitsugaya to speak to an unconscious Momo, who is still recovering from her injuries.

Bounts arc
Unohana is present for a captain's meeting called by Captain-Commander Yamamoto to discuss the Bount invasion, wherein he tells the captains to kill the Bounts on sight. When the Bounts infiltrate Seireitei, Mabashi uses Ritz to possess Shinigami in order to create infighting. Many who were possessed were brought to the 4th Division's infirmary to be healed. However, as she doesn't know how to remove the implanted doll, she orders all those possessed to be restrained and the puppetmaster captured. When Mabashi is killed by Suì-Feng, all of the possessed Shinigami return to normal. Unohana expresses relief that someone defeated the puppetmaster.

Zanpakuto Unknown Tales arc
Unohana is summoned together with all of the captains and lieutenants to Sokyoku Hill as Muramasa and the other manifested Zanpakuto Spirits appear before their former masters, declaring their rebellion. She orders Isane to treat Chojiro Tadaoki Sasakibe after he is injured by the Zanpakuto Spirits. After that night, Unohana leads her division in healing those who were wounded in the battle the night before, including Komamura.

She and her lieutenant are later visited by Lieutenant Nemu Kurotsuchi with a request by Mayuri Kurotsuchi that Unohana come to the 12th Division barracks to determine the cause of the Zanpakuto's rebellion. Afterward, she, Captain Jushiro Ukitake, and Captain Shunsui Kyoraku use the 4th Division's barracks to plan their strategies. When both Ichigo and Renji appear before the three captains, announcing that they have both subdued their Zanpakuto, they realize that the only way to restore control over them is to defeat them in battle.

After the Zanpakuto spirits attacked the 6th Division headquarters, Unohana appeared with the 4th division to heal all injured parties. Though she gets into a small rivalry with Captain Mayuri Kurotsuchi over the fact that she analyzed and developed a cure to his Bankai's poison. She is there to greet Suì-Feng and Yoruichi when the latter tells all in attendance that she has discovered the whereabouts of Captain-Commander Yamamoto.

Beast Swords arc
After all the chaos involving Muramasa settles down, she along with Captains Jushiro Ukitake, and Shunsui Kyoraku take charge of rebuilding Seireitei. She still is directing the healing of all those were injured from Muramasa's Zanpakuto rebellion. Soon after, she is made aware of the Toju phenomenon from reports similar to what happened to Rukia Kuchiki. While the rebuilding continues and the Tōjū is being dealt with, Lieutenants Nanao Ise and Isane Kotetsu notice several items from the 4th Division barracks go missing. Hanataro Yamada also reports that several of the chickens he was raising have vanished as well. They notice that the thief left tracks leading to the underground waterways. Suspecting it to be the work of a Toju and seeing Captains Unohana and Kyoraku send Nanao and Hanataro, along with Ikkaku Madarame, and his Zanpakuto Hozukimaru, to investigate the underground waterways (while secretly keeping an eye on them from the Research Department with Akon).

The group makes it back to the surface to report a Toju's death. They also mention that Hisagomaru had been the one stealing the items from the 4th Division. According to them, Hisagomaru explained that he had been manifested by Muramasa at the start of the rebellion, but had no grudge against his master. Despite all he tried, Hisagomaru was unable to return to his bladed form. Driven by despair, he hid in the sewers, secretly salvaging items to help him cope in his new surroundings, including Hanataro's chickens. Kyoraku asks where Hisagomaru is right now, only for the setting to change back to the manifested Zanpakuto, who had gotten lost yet again.

Unohana is also seen with Minazuki, along with a number of other officers of the Gotei 13 and their Zanpakuto, as they confront both Zabimaru and Senbonzakura when they accidentally destroy the buildings of the Shinigami Research and Development Institute.

Hueco Mundo arc
Unohana and Isane appeared alongside Captains Kenpachi Zaraki, Mayuri Kurtotsuchi, and Byakuya Kuchiki in Las Noches after the titanic battle between Ichigo and Grimmjow Jaegerjaquez. Her initial appearance effectively stops the approaching Exequias from doing further harm to Yastora "Chad" Sado, in which the leader of the group calmly orders a retreat. She then stops Isane from pursuing them, claiming that they are only there to heal the injured, not start more fights.

She proceeds to heal Chad and Gantenbainne Mosqueda, and orders Isane to go to the location of Byakuya Kuchiki as she feels something is wrong with Hanataro, who was originally sent with Byakuya.

Fake Karakura Town arc
Unohana appears alongside Mayuri Kurtosuchi after the latter announces that he can get Ichigo Kurosaki back to Karakura Town through a Garganta. She offers to accompany Ichigo back to Karakura Town, claiming to have faith in Mayuri's abilities, but not without adding a remark of how if he fails, Urahara will be disappointed, obviously irritating him. Before leaving with Ichigo, she orders Isane to remain behind and assist their remaining forces in Las Noches.

When Mayuri and Nemu open up the Garganta, Ichigo and Unohana jump in and head towards Karakura Town. As they are travelling, she asks Ichigo about his fight with Aizen, when learning that Aizen defeated him without using Shikai, Unohana is somewhat relieved. She then informs him that he is the only one who can stand up to Sosuke Aizen because he has not seen his Shikai. She tells Ichigo that his advantage is that not only does he have captain-class Reiatsu, but also that he hasn't seen Aizen's Shikai. She finally warns him not to witness Aizen's Shikai, stating that once he does, the war would be over. Ichigo thanks her and tells her that he will defeat Aizen.

As they make their way back to the living world, Unohana notices that Ichigo is making a path that is weak and brittle and asks that she be allowed to take the lead. Ichigo protests, saying it's unnecessary until she asks again even more politely, scaring Ichigo into submitting to her will. Once Unohana is in front of Ichigo, he comments on how she can make such a clean and sturdy path with captain-class Reiatsu, making note of the difference between them. Unohana asks him what he is referring to, stating that his Reiatsu isn't so different from her and as his wounds are healed, it is possibly because his Reiatsu is too rough and thus unsuited for the particular task. Ichigo objects, stating that if his Reiatsu was at full strength, he would be able to do better. Unohana doesn't believe his reasoning until Ichigo explains that the condition of his Bankai's shihakusho is able to give a clear example of how much Reiryoku he has left. Orihime had already healed him, but told him that it would take longer to replenish his Reiryoku, and since he went to help Rukia and the others, his Reiatsu never did get fully replenished.

He then points to his sleeve that he has left and says this is how much Reiatsu he currently has at the moment. Unohana then thinks to herself that it is impossible, as there is not even half of his shihakusho left, causing her to wonder if his Reiatsu is only at half. Unohana then realizes that she must have mistakenly thought that Ichigo's Reiatsu is at full strength because it was comparable to a captain's. She then asks Ichigo to run in front while she restores his Reiatsu to full strength as they travel. Ichigo questions if she is capable of doing that while they are running to which Unohana answers by explaining how healing Kido works and that restoring the Reiatsu once a body has physically healed is an easy task. Unohana then acknowledges to herself that if Ichigo's Reiatsu is only at half strength, then he may just be the trump card they need to defeat Aizen.

She later makes it back to the Human World and goes to where Hachigen and Hiyori are. Unohana finishes healing Hiyori Sarugaki and tells the Visored that she should be alright for the time being. Lisa Yadomaru asks if that means that she might not survive, to which Unohana explains that healing through Kido is no different from medicine. Unohana notes that she has finished fixing her physical structure. So as long as Hiyori doesn't give up on living, she will eventually wake up. Whether or not she gives up, is something she thinks Shinji Hirako would know better than her. As she begins to walk away Shinji tells her that he owes her one. Unohana stops and asks him why does he thank her, as she doesn't require thanks for saving the lives of her "allies". Shinji responds that he never said they were her allies as the Visored look on in surprise making him question what Hiyori would say in the situation. He simply says again that he owes her one.

Gotei 13 Invasion army arc
Unohana is present for a captain's meeting called by Yamamoto regarding disappearances in the Dangai. She listens to Mayuri's report that there is a time gap in the Dangai, which is expanding and may stop their ability to intervene in the Human World. Unohana asks him if there is a way to stop it, to which Mayuri replies that it can be fixed immediately, but he requests that a study be conducted to identify the cause. Unohana and Isane walk towards the Senkaimon and Isane says she felt a slight variation in Reiatsu. Unohana tells her to stop then and says they need more time. As the Reigai army meets, Unohana walks out on the streets of Seireitei, conversing with division members. When Kyoraku is locked up and Ukitake tries to plead with Central 46 to try and get him released, Unohana advises him not to blame them too harshly given that, as they see it, all the evidence is there and points to Kyoraku's guilt.

Unohana goes to the Shinigami Research and Development Institute with Isane, who concludes some of the data had been tampered with, possibly by Kyoraku while Unohana disagrees. She informs Isane that she has traveled to the Daireishokairo in regards to this matter and found that the man responsible is no ordinary Shinigami. Kageroza Inaba appears then and applauds Unohana on figuring out so much but she will have to wait to find out his motives as they will become clear soon enough. When the other captains succeed in getting through the Dangai, Isane attacks Inaba, who escapes only to be followed by the pair to an underground storage facility. Unohana observes Inaba's short sightedness as Kenpachi defeats his Reigai but Inaba accuses her of the same. Unohana is initially confused until Isane lifts her sword towards her, revealing herself as a Reigai all along who had gotten some samples of Unohana for Inaba allowing him to create her own Reigai counterpart. Unohana's replacement reveals itself, staring at her as Inaba asks what she is going to do now.

Unohana suddenly unleashes Bakudo #62. Hyapporankan on her counterpart, sending pillars hurtling towards her. Reigai-Unohana destroys her attack by using Bakudo #63. Sajo Sabaku. The Reigai then utilizes Hado #88. Hiryūgekizokushintenraihō, which surprises those around as it is done without incantation, however Unohana blocks it with the use of Bakudō #81. Danku. Unohana escapes the area while the others are distracted by the smoke of the attack. She later finds Yamamoto battle-worn from fighting the Reigai of Kyoraku, Ukitake and Unohana, helping him in a retreat and later treats his wounds. While regrouping, Renji arrives to report the situation, much to Unohana and Yamamoto's dismay. Unohana is then seen healing Yamamoto.

Later, Unohana follows Yamamoto to the Human World to aid their allies. Unohana then finds her Reigai-counterpart and confines her with a "Sajo Sabaku". She watches on as Yamamoto faces the enemies.[54] After the battle, Unohana takes Yamamoto to their temporary base and treats his wounds. She tells Renji and Rukia that while he is stable, Yamamoto will not be able to join the battle for a while. Renji initially insists they attack now while Inaba is injured, but Unohana strongly voices against such reckless action.

The Lost Substitute Shinigami arc
When Kisuke Urahara explains about his intentions to restore Ichigo's power in front of the Gotei 13, Yamamoto tells him to bring him the sword which will allow Urahara to do so. Unohana asks if he intends to agree to Urahara's plan and he replies that they were saved by Ichigo and thus it is their turn to save him, no matter the means. He then orders the captains and lieutenants to give their Reiatsu to the sword. Some time later, Unohana is present when Ichigo meets with the captains to request the return of Kugo Ginjo's body.

The 10 Thousand Year Blood War arc
Unohana attends a captain meeting where she is informed about Wandenreich's infiltration, and is ordered to prepare for war alongside the other captains. After the invasion of Soul Society begins, she eventually receives information on the Sternritter's ability to steal an individual's Bankai from the 10th Division. Unohana then notes that, upon examining their Reiatsu, the captains of the 2nd, 6th, and 7th Divisions had also had their Bankai taken. Some point afterwards, Unohana and several other members of the Gotei 13 are surprised to sense Yamamoto enter the front lines as their Captain-Commander's Reiatsu resonates throughout Seireitei. As she notices Yamamoto's Bankai take effect on Seireitei, Isane comments about her skin suddenly becoming dry. Unohana then distracts Isane from the situation by remarking on her acting rather girly. As she does so, she hopes that Yamamoto ends the battle soon, before he destroys Soul Society with his own power. Unohana and other captains are then later shocked to sense that Yamamoto had actually died at the hands of Yhwach.

During the aftermath of the battle for Soul Society, Isane begins to express concern about the decision for the 4th Division to remain inside. Mentioning that they might've been able to save more people, Unohana cuts her off and reminds her not to act on emotion. Seeing her begin to cry, the captain tells her to save her tears as the decision was the last order from the Captain-Commander. Unohana and the other captains later gather outside Seireitei to witness the arrival of the Royal Guard. Tenjiro Kirinji asks Unohana if she has been using the healing techniques he taught her, noting that there appears to have been a lot of deaths. When Senjumaru Shutara attempts to take Byakuya, Renji and Rukia to the Royal Guard's Tenchūren so that they can be taken to the Royal Palace, Unohana notes that their condition is too critical for them to leave Seireitei. However, the Royal Guard insist on taking them as Unohana's powers are not enough to heal Byakuya. Later, as Shunsui Kyoraku meets with Central 46, he invites Unohana in, saying that she will be in charge of teaching Kenpachi Zaraki Zanjutsu, calling her Yachiru Unohana, the first Kenpachi.

Later, after Kenpachi had recovered from his injuries somewhat and leaving a letter for Isane, Unohana leads Kenpachi into the lowest level of the Central Great Underground Prison under orders from Kyoraku to train the 11th Division captain to become strong enough to combat the Wandenreich. Revealing to have scarred each other's bodies in the past, both captains finally put their long-kept contempt for each other into actions and begin their battle to the death.

As Unohana and Kenpachi fight, the former is shown to be able to retain the upper hand against the latter, deflecting his blows with her free hand and feet. Praising Kenpachi for removing his eyepatch at the start of the fight, Unohana goes on to note that it also means that the strength he was currently displaying was his absolute limit. Calling him weak, the 4th Division captain wounds Kenpachi with a hidden knife, and states that those who hold their weapon in one hand while doing nothing with the other, look as if they aren't enjoying the fight. Noting that she had changed from the person he had looked up to, Kenpachi calls her out for using tricks she hadn't in their last fight. Knocking his sword from his hand and pinning him against the wall, Unohana tells him that she did not change at all; he just hadn't given her the opportunity to use those tricks on him when they fought last time.

Wondering if he has gotten weaker, Kenpachi explains that he had used to be bored with fighting before he met Unohana, and that when he fought her, he felt fear for the first time. Enjoying the fight due to this feeling, ever since then he had wanted to fight like her. Realizing that he may be about to die without being able to defeat her, Kenpachi can only shed a single tear as Unohana pierces his throat with her blade. Noticing the man almost pass out, Unohana mentions he had seemed defeated for a moment. Disregarding her question and continuing to fight her, Unohana thinks to herself that Kenpachi won't die, as he becomes stronger every time he comes close to dying, which is the mistake she made and the sin she imposed on him. As she reflects on their previous fight, Unohana continues to inflict great wounds on Kenpachi and heals them, noting that the limits he unconsciously placed on himself in their original battle are being gradually removed. She pledges to continue this until he surpasses her as Kenpachi begins to inflict wounds on her.

After receiving a devastating blow, Unohana reveals that she learnt how to heal just to prolong her fights. Recovering from her wound, she quickly unveils her Bankai and begins to attack Kenpachi once more. As the latter begins to overpower her, the woman thinks back to when they had first met once more, and how upon the conclusion of their first ever battle she had acknowledged him as worthy of the title of "Kenpachi". Content in the knowledge that he had finally unlocked his full potential thanks to her brutal guidance, Unohana smiles briefly before being impaled.

Unohana congratulates Zaraki and tells him he has finally won. He pleads with her not to die, as she laments to herself. That she no longer has anything to give, and that he now has everything/ Including that he has gained a lot in the exchange. She determines that she can now die happy knowing she has fulfilled her duty, and that he can celebrate in her place.

Video Games
Retsu Unohana appears in the following video games:
 * Bleach: Blade Battlers
 * Bleach: Blade Battlers 2nd
 * Bleach: Soul Carnival
 * Bleach: Soul Carnival 2
 * Bleach: The 3rd Phantom
 * Bleach: Flame Bringer
 * Bleach: Heat the Soul
 * Bleach: Heat the Soul 2
 * Bleach: Heat the Soul 3
 * Bleach: Heat the Soul 4
 * Bleach: Heat the Soul 5
 * Bleach: Heat the Soul 6
 * Bleach: Heat the Soul 7
 * Bleach: The Shattered Blade
 * Bleach: The Blade of Fate
 * Bleach: Dark Souls
 * Bleach GC: Tasogare ni Mamieru Shinigami
 * Bleach: Versus Crusade
 * Bleach: Hanatareshi Yabou
 * Bleach Advance: Kurenai ni Somaru Soul Society
 * Bleach: Erabareshi Tamashii
 * Bleach: Brave Souls
 * Bleach: Paradise Lost

Quotes

 * (To Sosuke Aizen) "I thought you would be here, Captain Aizen. No. I should not call you 'Captain' anymore, should I? Treacherous reprobate, Sosuke Aizen".
 * (To two 11th Division Shinigami) "While it is good to be energetic, please remain quiet inside the hospital. As long as you are still inside this building, your lives are in our hands. Please do not forget that."
 * (To Shinji Hirako) "The act of saving a comrade in need should require no thanks."
 * (Thinking about Kenpachi Zaraki) "I am strong. Stronger than anyone but you. That is why I must take your life this day. A hundred times, or even a thousand. That is why I must bring you healing. No matter how many times it takes. Until you are restored...to your true self. Until finally, you can surpass me, and move on to far greater heights...Come".

Trivia

 * Her birthday was April 21.
 * Her theme song, as chosen by Tite Kubo, is "Cold Light Of Day" by HALO.
 * When Retsu Unohana first appeared, her Zanpakuto had a curved blade, similar to that of a scimitar.
 * Though now known by this name, Retsu, which means "violent" or "fierce", Unohana used to be called Yachiru, during the time when she was the First Kenpachi. Yachiru means "Eight thousand/many flows", or "Eight thousand/many exiles".
 * Unohana has a column in the Seireitei Communication titled Tis the Season and another column titled Every Nook And Cranny.
 * She also publishes recommendations for sweet shops.

Voice Actresses

 * Japanese : Aya Hisakawa (2005 – Present)
 * English : Kate Higgins (2007 – Present)

all information on Retsu Unohana came from http://bleach.wikia.com/wiki/Retsu_Unohana