This is something thats been bothering me for a long time. He has a very strong set of morals despite the fact that he's working with Aizen. I think, and I believe most people can agree, that he's doing this because he thinks that its the right thing to do. He wants to pick the path of least bloodshed, also he considers some hollows innocent while looks down upon others. Looking at Hollows that have befriended Ichigo, its obvious that there are some that are not evil. For this reason I think that Tōsen just saw the flaws in soul society and believes that Aizen will be able to fix them if he gains power. So I can see Tōsen eventually coming to the realization that Aizen will only make things worse and sacrifice himself to save soul society or re-join soul society. Even now I don't want to believe that Tōsen has turned against everything and might just be working to defy Aizen at the last possible second to prevent any bloodshed. However, given the last few chapters I can see that this is just wishful thinking for me who always held him in such high esteem. But, what do you guys think? Am I completely mistaken in this or do you think that Tōsen might one day be redeemed.