What happened to your D1 and D2 characters?

Actually that isn't entirely true. A sorceress who fought aginst the evils is killed in the wizards backstory but I have doubts its the sorceress from D2 and believe its just a random adventurer. I can post reasons if you want. The assasin who kills her however us definately a guy so he can't be the female assasin from D2. Additionally hes getting his targets from the head of the wizards order whereas the D2 assasins order was specifically tasked (if I remember right) to kill corrupt mages so it may not even be the same group. As for the Necromancer hea never confirmed as dead we just run into the apprentice of one who fought against the prime evils. Just remember the heroes of the games aren't the only ones fighting, and dying in these wars.

There's corrupted and posessd, Blood Raven was corrupted while the warrior was possesed. That's why Blood Raven empowered by Diablo's evil was still a humanoid being using familiar weapons, a bow and an army. The warrior was possesed which meant you wind up with a different being Diablo rather than one with just a new attitude and abilities. I'm not sure about the wizard becoming the act 2 summoner though I though that he and the monk just dissapeared.