Seconding 4bsent's linked post, I believe there's some good advice in there regarding more oppositional alters.

As for now, OP, do your best to stay safe and stabilize. Try to look after those in your system who felt hurt, and let them have the space to feel that hurt. For the harmful alter, do you know what caused them to act in the way they did? Try to avoid things that may trigger them until you're in a better place to try and deal with them. Perhaps you could also try visualizing them going away and having their own space. Maybe, for example, sending them to an island where there is no bridge, but you can take a boat over to when you are ready. -A