I think it's been excepted that the theory that INFP's can't be villains has been put too rest. And these two MARVEL super villains, Nebula and Electro, are perfect examples of evil INFP's.
Let's start with Electro. Electro is motivated by an uncontrollable rage. The thing about INFP's, is that they are pretty easy-going people. But once they are pushed past their limits and really pissed off, their reactions could be scary because they have inferior Te. That function being inferior means that it is the least well developed. And that means that they have very little control over it. So when an INFP is put in a situation of frustration and anger, they go on a mindless rampage. This perfectly illustrates Electro. You can use his scene in Times Square as an example. So much was going on and he was having a rough day. And so when he had just had enough, he almost murdered everyone around him without paying attention. That also shows his Fi. INFP's tend to let there emotion get the better of them and they forget the other people around them because their emotions now are circling around themselves. That's where Electro's Fi is. While Fe prefers to see things through the feelings of others, Fi makes decisions based on their own feelings, which could actually be good sometimes, but in Electro's case, it went downwards. So when he get's really angry with Spider Man, he stops thinking about the innocent people around him and starts thinking about how much he wants to kill Spider Man and he' willing to get others hurt to do so. There are small signs of his Ne. I mean, if talking to imaginary Spider Man isn't total INFP, than I don't know what is. And then lastly, there's hi tertiary Si function. The small misunderstanding he had with Spider Man was something that he wasn't willing to let go of. Si being one of his poorly developed functions, his grudge against Spider Mangoes to extreme levels.
Then we have Nebula. For a long time, people have not been able to type Nebula. And in that long time, I used to think she was an ISTJ. Being one of the most deadly assassins in the galaxy, it would be really easy to mistake her for one of the ST types. But after a lot of thought, I concluded that she was actually an INFP going seriously mad. Along with Electro, she also illustrates perfectly an inferior Te. Because of her jealousy for Gamora and her hatred for Thanos, her anger has led her to make some poor, not very well thought out decisions. In the movie, Guardians of the Galaxy, in her fight with Gamora, you'll notice that her fighting style wasn't as well coordinated as it could have been. Instead, she was putting rage into her every move. While you can tell that she was a very well trained fighter, her style was mainly trying to viciously slaughter Gamora in any way possible. Also, I thing Nebula definitely follows the trait of INFP's being emo. Like, her entire back story is based on family issues. And just like Electro, Nebula has an Fi that has gone the wrong way. The war going on between the Kree and the rest of the galaxy really doesn't matter to her. The only reason she does what she does is to avenge herself.
I think most INFP villains are built on inferior Te. Any way thse are my examples. I would love to hear some of your examples of INFP villains as well as your thoughts on this post.