After his death at the hands of Shinigami Captain Mayuri Kurotsuchi, former Arrancar Scientist and 8th Espada Szayel Aporro Granz fell into the depths of hell alongside fellow Espada Aaroniero and were overwhelmed by the surprise attack of Shuren and his Togabito followers.
After recovering from his defeat Szayel ventured deeper into the wastelands in search of a way to return to his precious Hueco Mundo. Little did he know that the atmosphere of Hell was slowly transforming his soul into a sort of Togabito/Arrancar hybrid, he now found himself bound to Hell.
Many of the other Arrancar also found themselves trapped within Hell such as Baraggan, Nnoitra, Zommari, Yammy and many of the Fraccion and Numeros. Though they had felt the fighting going on between Ichigo and the Shuren's group they chose not to get involved.
Despite the Kushanada (Guardians of Hell) being immensely powerful and able to manage lower souls, the great numbers of newly arrived Arrancar souls proved to be quite problematic for them as they were actually able to put up a great resistance, especially considering that the Arrancar quickly learned that devouring the souls of other Togabito within Hell increased their power. This, along with the fact that when they devoured the souls they would just keep coming back over and over started a great conflict between them and the Guardians.
The former Espada began dividing up Hell amongst themselves, appointing themselves "Lords" of their own territories. Most of the Arrancar (who were now Togabito Hybrids) had no interest in returning to Hueco Mundo as they now had much more rule then they did before and an infinite amount of souls, though others such as Szayel still planned to return. He had not yet acquired enough power to break his chains however so for the time being he decided to take control over a section of the second layer.
Much later he would eventually gain the necessary power to free himself after devouring the souls of Zommari, Aaroniero and Yammy and return to Hueco Mundo.
Years after this he would begin the creation of the Cyber Hollow in order to track down AF, and then discover the ability to travel time and space, venturing into the far future, gaining God-like Power and returning only to eventually be defeated by AF, his own creation.
Powers and abilities:
Originally after recovering from his defeat at the hands of Shuren, Szayel's power was not much different from that of his previous self. It was not until after he began changing into a Togabito Hybrid and devouring thousands of souls that he started to become much more powerful, eventually overwhelming Aaroniero in combat and devouring his soul as well. Once he did this he had enough strength to do the same to Zommari and then over time Yammy.
He possess some unique abilities such as tentacles (similar to those of his Resurreccion) which he can fire from within his sleeves. He is also able to fire powerful energy blasts similar in appearance to Bala.
I like how this turned out. I'm probably going to make Hell versions of the following:
Baraggan (Need to redo his)
Nnoitra (Probably will redo his)
Zommari (Need to redo his)
Aaroniero (REALLY need to redo his)
Yammy (Need to redo his)
and probably some others..
Szayel looks really buff O.o But its mostly due to his outfit.