I have no idea.
you can also make references. like if their ocs edgy you could do something like 'i bet he mains reaper in overwatch' or something idk-
So basically it'd go something like this;
(Echo:) i'm the first character. *NERVOUSLY SHAKES*
Azazel: *EARRAPE ECHO VOCALOID* or something because i can't make that much puns involving Echo's so yeah
Echo: ok instead of Azazels bad joke what do people got for me today
THIS IS MY FIRST FORUM GAME DON'T JUDGE ;-;