Fighting a demon wait what even is that thing?

Preparing for some huge demon to rip him in half John does the only reasonable thing he could," ARE YOU INSANE?" He yells, "HOW AM I SUPPOSED TO KILL A DEAMON"

"Ohh i don't know but it's behind you you know. "The priest smirks

*ohh shit I'm gonna die* diaz thinks as he turns around. "Wait what even is that? Is that slime supposed to be a demon?" he asks feeling slightly less doomed.

"I have a name you know. "states an extremly upset slime" Not like you would care summoning me just to kill me."

"you can talk? How does a slime even talk?" Asks A dumbfounded Diaz.

"Well I'm not really talking I'm just in your head,"the slime says smugly,"and the name is Diaphanie, you Neanderthal."

"dia what? Wait how are you in my head?" Diaz asks.

"You summoned me so why don't you figure it out before you make yourself look like a bigger idiot, I mean no one else can hear me."Says Dia,"Ohh and call me mistress Dia seeing as how your to stupid to remember it."