Sorry. I've become accustomed to writing out vague things. My family uses them too much in general. And it doesn't have to be just one person on the murderer list. It could be a sort of group effort.
To be honest, I haven't planned who the characters would be too much. It seems a little OP to make the character with the names a player, as they could pretty much run the entire thread and any hiatus on their end might bring it to a lengthened pause. Better off to make xir an NPC everyone could control the actions of to a degree (as long as they don't write extremely out of character). Far as I can tell, the goal would be getting your name off the being's arms and/or befriending xir enough that you can throw off the scent and buy some time to figure out the first part, as there's a chance xe might kill everyone with those names and be done with it in an attempt to subvert a prediction.
My initial idea for the interaction was that the being would be hostile until realising that maybe attacking openly would lead to death for xir. Tension would still be high, though, and xe be trying to figure out just who is the enemy and who isn't. Interacting with xir would be forced, in a way. It was a headcanon that being so associated with humans would get the being booted from xir home, and one that I forgot to point out. Sorry about that. Xe'd be forced to live on whatever xe could and have to stay wherever they could, although close enough that xe could keep an eye on the people on their list. Xe'd also have to analyse the current technology and lifestyles to avoid being seen as a threat or being noticed by everyone, as it'd be very different from whatever they have.
Thank you for pointing that out. I'll try to add more detail the next time I make an interest check.