Aizen was indeed a captain in the Bleach anime and manga series. He served as the captain of Squad 5 in the Gotei 13 before betraying Soul Society and becoming the main antagonist.
Aizen’s Time as a Captain
Aizen first appeared in the series as the mild-mannered captain of Squad 5. He often maintained a gentle, thoughtful expression on his face and spoke politely to his subordinates. This helped conceal his true manipulative, cunning personality.
He served as a captain for over 100 years, having reached that rank sometime before the main storyline began. During his tenure as captain, he conducted various secret experiments and manipulated events behind the scenes to gain power and further his plans.
Some key points about Aizen during his captain days:
- He recruited Gin Ichimaru and Kaname Tōsen who became his close followers.
- He hollowfied several Shinigami including Kisuke Urahara and the Visored in secret experiments.
- He masterminded the events leading to Urahara’s exile and took his place as captain of Squad 5.
- He manipulated the central 46 members to have Rukia Kuchiki executed.
- He faked his own death after the execution was stopped, revealing himself as a traitor.
So while Aizen presented himself as a model captain devoted to Soul Society, he was furthering his villainous plans the entire time before finally defecting and declaring war.
When Did Aizen Become a Captain?
The exact timeframe when Aizen attained his captain rank is unclear in the manga and anime.
Some key clues and estimations:
- He was already a captain when he did hollowfication experiments on Shinigami including Urahara over 100 years before the main story.
- Gin Ichimaru became a captain about 100 years before the story too, likely under Aizen’s guidance.
- A captaincy lasts a very long time for Shinigami who can live for centuries. Most captains hold their rank for many years.
- Aizen appears middle-aged, suggesting he had been a captain for a considerable time already.
Given this, it seems likely Aizen first became a captain at least 200-300 years before the start of the main storyline. He was then able to build up his reputation and power base in Seireitei over a very long period of deception.
Which Squad Did Aizen Lead as Captain?
Aizen served as the captain of Squad 5 in the Gotei 13.
Some key facts about his tenure as leader of this squad:
- He was promoted to Squad 5 captain after Kisuke Urahara’s exile.
- Squad 5 specialized in kido and healing abilities – playing to Aizen’s intelligence.
- His lieutenant before Momo Hinamori was Shinji Hirako, the future Visored leader.
- He remained captain for over 100 years until defecting from Soul Society.
- Momo Hinamori was extremely loyal to him as his lieutenant.
So Aizen led Squad 5, one of the 13 Court Guard Squads under Captain-Commander Yamamoto. He manipulated everyone around him with his gentle personality for years as the squad’s captain.
Who Took Over Squad 5 After Aizen?
After Aizen defected and revealed himself as a traitor, there was an empty captain position for Squad 5.
The new Squad 5 captain who replaced Aizen was Shinji Hirako, the former captain of the squad before Aizen took over.
Some key points about Shinji resuming leadership of Squad 5:
- Shinji had been the previous captain until Aizen arranged his hollowfication experiments.
- He then lived in exile with the other Visored for years afterwards.
- With Aizen revealed as a traitor, Shinji was allowed to return to Soul Society.
- His experience and strength made him a good choice to restore order and morale in Squad 5.
- However, Momo Hinamori had a very hard time accepting him due to her past loyalty to Aizen.
So Shinji Hirako, the former leader deceived by Aizen, became captain again to guide Squad 5 into a better future after being misled for so long.
Did Aizen Have Any Other Positions or Ranks?
In additional to being a captain for over 100 years, Aizen also held these other ranks and positions:
- Lieutenant of Squad 5 – He served in this role under Captain Hirako before being promoted to captain.
- Seated Officer in Squad 5 – His earliest known position was being a seated officer under Shinji Hirako
- Kido Corps Commander – He served as leader of this corps for a time centuries before the main story.
- Shinigami Research and Development Institute researcher – He conducted secret experiments here.
- Academy instructor – He taught classes at Shinigami Academy many years ago.
So Aizen held various important seated officer and leadership roles in Soul Society before becoming a captain. This allowed him to gain influence and position himself for his later manipulation efforts.
In conclusion, Sosuke Aizen did indeed serve as a captain in Bleach for over 100 years. He was the captain of Squad 5, deceiving everyone around him and manipulating events for decades to gain power while hiding his villainous ambitions. His tenure as a captain ended when he faked his death and defected from Soul Society, finally revealing his true nature.