i didn't really get nicknames from anyone outside of my family growing up; there's "court" which i'll let people use if we're reasonably close and "court-court" which is childish and i'll only let like, immediate family use because i haven't actually been called it since i was a kid
i've had a plethora of other nicknames from online stuff (mato, chupa, lumi) and the only one that's really relevant because i've got someone who knew me back then (aside from peace) is actually "chupa"
...because i, uh, i had a good stint of being really fucking into cryptids. i don't know, i have nice years where i hyperfixate on random topcis and learn a lot
"bella" comes from my time in the hetalia fandom though; i played belgium when aphdr was pretty much just starting, we didn't have a humanized name for her, and we sort of went by our countries' humanized names in irc and ooc stuff
so we went with "bella" and i've never gone back, lmao. i have some sentimental stuff attached to it too, but by and large it's just... a nice name and i like it and everyone knows me by it anyway so there's no sense in changing it!
for black, uh .. ... "black" is actually a nickname his dad gave him (it matches white) and it's a ref to alcohol/black and white sake. otherwise, his actual name is william and "will" is a pretty good shorthand for that that white uses
aligula doesn't have one!! but she has a title (queen of monomania) and i know i headcanoned that she's had "ali" as a nickname before, since the question came up at her soulmate finding party
i did milla and crys in here too even though i'm not playing them atm because 1. milla's my boo and mimi is cute and 2. crys has a canon nickname let me have this
the king of despair is, well, actually a nickname/title in of itself, but he's also been known as "blue" "the devil" "the fallen" "the watchman" and ... yeah