Heaven

" From now on, I will stand in heaven"

-Aizen Sosuke

Heaven had always been a lure for Aizen. His obsession with becoming God had started when he met Urahara Kisuke for the first time and became acquainted with the man's inventions. The one invention that tickled his fancy was Urahara's pride and joy, the Hogyoku. It was because of this invention that Urahara got exiled from Soul Society.

After Urahara's exile, Aizen concentrated all his efforts into three different fronts: finding the Hogyoku, toying around with his new hobby, Hollowification (the process by which shingami are turned into hollows), and the recruitment of different shinigami to rally to his cause.

The results of the recruitment venture were somewhat successful as he managed to recruit the Ninth Division Captain, Tosen Kaname, and his lieutenant, Ichimaru Gin. On the Hogyoku and Hollowification fronts, Aizen was having much more trouble. With the Hogyoku, all his research on where it was ran into a dead end as he couldn't, for the life of him, figure out where Urahara put the object that would lead him into godhood.

With the Hollowification, Aizen was having a difficult time without the Hogyoku. Without the Hogyoku, he could only create experimental hollows, like the one who had killed Shiba Kaien. After the death of Shiba Kaien, he decided to lay low and wait for things to play out. When Kuchiki Rukia vanished in the human world, he knew something was up, and put forth all his resources to finding her. It was also during this period that he murdered everybody in the Seijotokyorin and made it seem as if they were still alive while he or either of his two cohorts stayed there at any given time.

While he was in the Seijotokyorin, he did research on Kuchiki Rukia and found out that the gigai she was using had the Hogyoku inside it. He sent Kuchiki Byakuya and Abarai Renji to retrieve her and they did that without a flaw. When Kurosaki Ichigo and his friends invaded Sereitei, Aizen knew it was time to put his plan into action. The first thing he was fake his death so it could be blamed on the ryoka. The second thing he did was to constantly move up Kuchiki Rukia's execution date so he could get the Hogyoku sooner. Both aspects of his plan went off without a hitch and he was able to get the Hogyoku from her gigai, albeit injuring Abarai Renji, Kurosaki Ichigo and the Seventh Division Captain Komamura Sajin in the process. He seemingly got caught by two shinigami but managed to escape with the Hogyoku and his two subordinates because he made an alliance with the hollows. After he escaped Soul Society, he was free to pursue his dream of godhood by using the Hogyoku to create his own army of arrancar and by acquiring the Royal Key so he could kill the King of Soul Society.