I’m scared, I have a head mate that is fictional and that’s never happened to me, usually the voices in my head are just different variations of my own voice, I don’t want to scare him off but it also concerns me a bit since this is all new to me. He stopped my other voices from fighting randomly and it caught me off guard, but I’m grateful for what he did. Any advice for making new head mates feel welcome?

Hey there! First of all, no need to be scared/freaked out. It sounds like this headmate is here for your benefit, and you’re not in any kind of danger from him. It sounds like he has your wellbeing at heart by stopping the fighting between your other voices. ^^ 

I’d say the best way to make them comfortable is to try to be at ease with him– which may take some time! Until you are at ease, you can verbally/mentally welcome him, and thank him for his help. You can tell him you may need some time to be comfortable, and I’m sure he’ll accommodate you. Try to chat back and forth with him and see what he’s like, and what he wants. If he’s a fictional character, find out if he’s comfortable with his source material, and engage with it. You can also put out canon calls to find other people from his source, to interact with.