All For One/Relationships

His brother
In the past, All For One cared deeply for his younger brother, as he was the only family he had. However, All For One would insult him, labeling him as pathetic and fragile as he had his bodyguard go easy on him before imprisoning him. In return, All For One's brother had a strong sense of justice and did not back down from opposing his brother's evil deeds. To end his rebellion, All For One attempted to get him to submit by giving him a quirk, unaware that his brother already had one and his act only contributed to the creation of One For All. All For One's younger brother attempted to defeat him with his newly merged Quirk (now called One For All), but lacked the sufficient power to do so.

It is unknown if All For One killed his brother in battle, but the latter's quirk was passed down to an unknown successor, in the hopes that someone in the future would eventually stop his evil older brother once and for all. Because of his brother passing on the Quirk, All For One sought One For All with each successor.

One century later, All For One meets his brother in the world of One For All, when Tomura attempted to steal the Quirk from Izuku. All For One rebukes his brother's decision to remain with Izuku, calling the latter unworthy of such incredible power. The younger brother retorts that All For One can never comprehend Izuku resolve of self-sacrifice and that is the reason One For All will follow the young hero. The younger brother, with the help of Nana Shimura, expels All For One and Tomura from the world of One For All, thwarting their attempt to steal the Quirk yet again.

It's possible one of the reasons All For One desires One For All, besides its power, is to reunite with his younger brother through his vestige, since he failed to bring him to his side in the real world.

Tomura Shigaraki
All For One groomed Tomura as his successor. He was the one who rescued Tomura from the streets after the incident of killing his family during his childhood.

It's later revealed and heavily implied by All For One's brother that the main reason All For One groomed Tomura to be so hateful of the world and of All Might was in order to foster a hateful will; through a stronger willpower, it would be possible to overcome the will of a One For All user, bypassing it's natural resistance to being stolen.

All For One is deeply invested in Tomura's growth and was pleased when Tomura finally developed a plan to achieve a goal on his own. Although well aware of his immaturity, he works to mold him into the successor he dreams of him being. When the police and Pro Heroes capture Tomura, All For One retaliates with force before teleporting Tomura and his friends to safety.

It is unknown whether Tomura is aware or cares that All For One killed his grandmother, however, it does appear that All For One truly cares for Tomura, having a similar relationship like All Might has with Izuku Midoriya. All For One even allowed Tomura to carry on his family name, Shigaraki, when renaming him. Instead of punishing Tomura as any archetypal villain would do to their apprentice, All For One instead encourages Tomura to simply start over as many times as he needed to and that he will always provide him with help. His care goes so far as to urge Tomura and his friends to leave the battlefield with All Might, keeping the Symbol of Peace distracted and entrusting Tomura to continue the fight in his stead.

Although All For One groomed Tomura with the intention to demoralize All Might and even scorn the lineage of Nana Shimura, it is evident that he supposedly grew to care for his adoptive son and is the only person to whom he has shown genuine love to, arguably besides his brother, even if greatly motivated by evil.

After Tomura received the All for One Quirk, All For One (or at least a vestige of him in the Quirk) attempted to take control of Tomura's body, and use it to steal the One For All Quirk from Izuku during his battle with him. Tomura regained control and rebuked his master, saying he wanted to follow his own will, and become greater than he was.

Tomura begins to hate All For One when the latter repeatedly attempts to take over his body to steal One For All. All For One doesn't mind though as he cheers on Tomura while he resists his control as it proves that Tomura is strong enough to be his successor. He later advises Tomura to retreat and let his body heal while he waits for his body to adjust to his new power. As the battle continues, however, All For One once again takes control of Tomura's body, noting that the more hatred Tomura has in his heart, the more his consciousness takes hold of his protege's body. All For One remarks how Tomura should pay back for losing to Endeavor and Deku, saying that it is all for his sake; this implies that All For One only saw Tomura as simply a means to regain power and had no true affection for Tomura.

This is further shown when he called himself in Tartarus his "real body", implying that he sees Tomura as nothing more than an additional host for his consciousness. When Tomura attempted to regain control, All For One refused, stating that this was the fruit of Tomura's labors, and when he refused to be a pawn, All For One replied that he was no mere pawn and someone very "near and dear to him". However, when he finally escaped Tartarus he stated that this is the story of how he would become a more perfect demon lord. This heavily implies that he had no affection for Tomura, and after his body was heavily damaged by All Might, he spent all those years of raising him and nurturing his hatred in order to both gain a new healthier and stronger body use Tomura's hatred in order to steal One For All thus allowing All For One to rise once again with even greater power. This would make sense as All For One is notorious for manipulating people for his own benefit.

In spite of this, when conversing with Spinner, All For One said that he greatly respected Tomura's will, and that once Tomura's body healed, both their desires would come to fruition; this could insinuate that even if All For One never cared for Tomura personally, at the very least he respects Tomura and his resolve, though he could have just told this to Spinner to put him at ease. Additionally, while All For One is trying to remake himself using Tomura's body, he also has no problems with Tomura proving stronger. At the least he is reluctantly willing to let Tomura usurp him as the true user of All For One and the symbol of Evil if it comes to that provided Tomura proves stronger.

Kyudai Garaki
All for One puts deep trust in his physician, exclaiming that Kyudai's insatiable curiosity and inquisitive nature has always been the source of All for One's strength, and thanks the doctor from the bottom of his heart, going so far as to call him his friend.

All For One met Kyudai when he was at his lowest point, after being ostracized from society due to his Quirk Singularity theory. All For One, on the contrary, believed in his theory and gave him his full support. Thanks to this, Kyudai became one of his most loyal followers, giving to him his original quirk as a proof of this. Since Kyudai has been working for him.

All For One tasked Kyudai with several assigments like making Nomu, searching for Quirks for him to use, and overseeing Gigantomachia, among others. All For One is the only one that Kyudai entrusts with his 'children' (Nomu) and the knowledge of his appearance. Kyudai was also the one who treated All For One's injuries, using his talents as a doctor to help rebuild All For One's body after his battle with All Might.

Kurogiri
All For One ordered the creation of the Nomu Kurogiri using the body of Oboro Shirakumo. Although programmed to obey his commands, and the memories of his past life suppressed, All For One granted him with intelligence of his own and some traits of his former self's personality was retained, especially Oboro's caring traits and his drive to help others, especially people close to him.

All For One wanted to create Kurogiri in this way because he entrusts him into looking after Tomura and ensure that he is given the proper guidance. He also told him the location where he hid Gigantomachia in case he needed it to protect Tomura.

In the few interactions that are seen between the two of them, All For One shows some respect and appreciation for Kurogiri despite being a Nomu, valuing his honest opinions. During the Underground Masquerade Incident, All For One tried to teach Kurogiri the dichotomy between heroes and villains, and how the relationship between a person’s will and their Quirk is what defines one and the other.

Gigantomachia
Gigantomachia was his bodyguard when All For One controlled the world from the shadows and said loyalty has not waned despite All For One's downfall. For his part, All For One considers Gigantomachia an essential piece for Tomura Shigaraki and the resurgence of the League of Villains. Because of this, All for One hid Gigantomachia in the mountains as a means to help preserve his dreams.

However, the same loyalty to All for One that makes Gigantomachia useful also makes him difficult to control for others. He initially refuses to accept Tomura as his successor because he believes that Tomura is not All For One's equal. It is noted that a recording of his master’s voice can quickly soothe him to the point that he will purr. However, he came to accept Tomura after seeing his reawakening in action.

In spite of Gigantomatchia's unyielding loyalty to All For One, he still chose to abandon Gigantomachia along with the rest of the League of Villains.

All Might
All For One and All Might loathe one other. All For One holds a deep hatred for All Might for crippling him, defeating his comrades, denying his ambitions, and being called the symbol of peace for this. All Might sought retribution against All For One for murdering his master. It is revealed that All For One viewed All Might as huge threat who could defeat him and groomed Tomura Shigaraki succeed him.

He states to All Might that he needed a successor because of the injuries All Might inflicted on him from their first battle. Due to the crippling injuries All For One received, he can never be in his prime again. It's also heavily implied that All For One is in even worse shape than All Might is. While All Might's injuries limited his use of One For All, All For One is not capable of living without a life support apparatus keeping him going.

During their second battle at Kamino Ward, All For One confesses that he still has nightmares and mental trauma from their first encounter from when he saw the look on All Might's face after ripping All Might's guts out. All Might seems to not only be the first to defeat All For One, but also the first to ever severely scar him mentally.

All For One enjoys belittling and ridiculing All Might, even relishing in breaking All Might's spirit by revealing that Tomura is Nana Shimura's grandson. He also enjoys watching All Might become riled up by belittling Nana's heroism and death. In their second battle, All For One aims to take everything from All Might, his image, and pride by revealing his gaunt form and weakness to the public.

Even after being captured, All For One continues to play with and taunt All Might, using any and every opportunity to strike at his nemesis. Despite being defeated by the latter, All For One took his loss in stride and mocked All Might for not dying when he had the chance, confident that his pupil will become stronger to take over the League of Villains. All For One is also aware of the fact that Izuku Midoriya is the current bearer of One For All and criticizes All Might for being a pathetic teacher.

Nana Shimura
All For One thinks Nana was a pitiful woman. He mocks her commitment to ideals and disparages her strength and, by his admission, declared the latter died a pathetic death.

All For One tarnished her memory by knowingly taking in and grooming her grandson to be his successor.

All For One meets Nana in the world of One For All, and insults her in front of Tomura. Nana recognizes her grandson and isn't pleased with the situation. She and the first user of One For All work together to thwart All For One's attempt to steal One For All.

Best Jeanist
All For One praises Best Jeanist's skills and proficiency with his Quirk. However, he deems that his quirk requires too much skill and therefore it's useless to him. All For One blast a gust of air that, in the long run, costs Best Jeanist a lung. Best Jeanist is terrified of All For One's sheer power and skill.

Deku
So far neither Izuku or the elder Shigaraki have had much time to interact. Nonetheless, All For One was made aware of Deku being All Might's successor and the new holder of One For All making Deku All For One's target. When they spoke in the vestige world he mocked Deku for his weakness and call him being chosen a mistake. While he acknowledges Deku as a threat he is still dismissive of him due to Deku's lack of experience.