Discussion Bleach

It was supposed to be explained at the end of the manga's last arc, but it was instead relegated to a novel. Hopefully they put it in the anime.

 

291 was good. Shinji and Aizen playing 4D chess with each other Aizen had the upper hand at the end. RIP Tosen, he was just a hopeless romantic at the end Ichigo is here!!! Aizen count your days ()

 

Just to clarify: Tosen was not in love with Kakyō (the woman who was killed). He just valued her friendship and ideals that much.

Well, I suppose you could say he loved her. But it was a platonic love.

PS:
I don't consider it a spoiler to reveal her name, since it comes from supplementary material.

 

Yes. And, as I said: he valued her friendship and her ideals. He saw those ideals betrayed by the very system he thought would uphold them, and decided he would upend that system along with Aizen, whom he also came to care for genuinely.

PS:
Again, when it comes to the novels: it was revealed that Tosen (whom Aizen affectionately addressed as Kaname) was the one person that the psychopathic Aizen genuinely did care for. This is why I don't think he saw Tosen as a guinea pig when it came to Hollowfication. He likely did all he could to make sure Tosen suffered no side-effects.