Is it normal for me to still resent my brother for making fun of my deformity when we were children?
Did he treat everyone that poorly?
I don't think so. It's just that I was physically disabled since my birth.
Words can hurt more than people realize. It is understandable that you did not like what your brother was saying to you all those years, he was in the wrong for that.
Whatever, I'm not going to be nice to him, I want to gain upper hand in this family game.
It sounds like you're still hurt by this, and even though what your brother did was wrong, it would be wrong of you to bring it into your adulthood by being cruel to him now. Instead, since you're now both adults, you should tell him how much he hurt you and try getting some sort of closure from those tough times as children.