A/N
my apologies I should have said this earlier this is slightly AU. Also Sorry guys i don't think I explained it well in the story but in chapter 1 prologue during the talk with Aizen what I meant by " if I was truly immortal I would've beat you or something, what I meant was Ichigo was destroying aizen so badly that his "immortality" or the hogyoku were unable to keep up with Ichigo in the state "HORN OF DAMNATION" and so aizen died only breaking a single horn even after aizen got stronger with fight and please keep this in mind this is slightly AU.