I noticed that the tag said villain if the main character becomes a villain I'm not going to like it but I'll still read it and won't let me post so I'm going to say random words until it does so beep boop bop bop
Well this is a bit of a spoiler but i will say it since you asked so nicely ;) It depends on your point of view, whom you consider a villain. There is one arc in future where her actions might be questionable for some, but she has a reason for them. And it is a very convincing reason....