In Psychoborg, people who are friends with Psychoborg tend to call him "Psycho". Psychoborg calls Astra "babe" while Ira who is her fiance calls her "beautiful". Highwulver calls Psychoborg "lad". Castor tends to call everyone they like "honey". It's a term of affection they give all their friends.
As for Frankenstein... be warned that some of the nicknames are not flattering. Igor calls Prometheus (the monster) "Prom". Victor Frankenstein tends to call his little brother William a "whelp" or "vermin", his own father "the old man" and Prometheus "the wretch". Yeah, Victor is not a nice guy.