Which sister was the bigger monster, Blanche or Jane?

It’s really left up in the air. But I would say ultimately…Jane. But then again, it’s Blanche’s fault for her even being in that situation….i just don’t know! It’s a great discussion to have though

Also, Blanche is in her situation because she tried to murder her sister. Lest we forget, and not to excuse Jane’s behavior

Blanche. She treats Jane like a servant at the start of the film. Can't blame Jane for snapping.

Blanche used Jane's drunken state (at the accident) to make her be her slave. Later in the film, she says "I'm still in this chair", never admitting it was her own fault that she caused the accident. At the end of the film, she confesses. Jane says "you mean all this time, we could have been friends?"

If Bette hadn't bossed her off Charlotte, she would have been playing the villain a second time. Think of how those scenes with Agnes Moorehead would have played. And she would have killed AM too! Bette would have said "you're nothing but a vile sorry bitch and MEANT IT.