Most of them get levelled at Urien, whose nicknames include:
Urine, Piss boy, Golden boy, Poorien, Boorien, Durian, Cheekbones, and... Worst Boy.
Ambrosius, the demon in the prologue, has the hilarious fan nickname of "AmBROsius" or "Bro" for short.
I'm pretty sure Rekki has been called "Wreck it Rekki" more than once by more than one person at this point for... yeah, obvious reasons.