When you think about it, Chara is really the hero of the genocide run because they're the one who finally puts a stop to you and forces you to true reset. Especially how they tell you not to genocide again if you do it a second time. <<<<This! THANK YOU!!
I've never thought of it this way, before. I've always thought of it as his last battle, which he's trying to keep you in forever. But no, he knows that you can reset. He's fighting to make you quit. He's fighting for a chance to see his brother again.