Is it a Belmont?
Castlevania: Rondo of Blood
Belmont (Richter Belmont)
“... and that's for pooping on my lawn. I'M the only one that gets to do that!”
Deadpool (Ultimate Marvel vs. Capcom 3)
[Fun Fact: Due to a programming bug, this is directed to Spencer, when it's supposed to be for Amaterasu.]
"The Moon Haunts You!"
Moon Knight
Akuma
Banned (Super Street Fighter II Turbo)
Secret boss character not balanced for competitive play + air fireballs
BlazBlue
Guilty Gear
Castlevania: Bloodlines
Not a Belmont (John Morris & Eric Lecarde)
"Wubba wubba, I'm in the pink today, boy!"
Terry Bogard (Fatal Fury Special)
"Extermination!"
Ultron
Vergil
Legal
Dark Souls
Demon Souls
Castlevania: Curse of Darkness
Not a Belmont (Hector)
"Defeating you takes less effort than smacking a baby... not that I'd ever do that!"
Akuma (SNK vs. Capcom: SVC Chaos)
"Well? Are we taking them down or not?!"
Deadpool
Noriaki Kakyoin
Banned (JoJo's Bizarre Adventure: Heritage for the Future)
Nowadays, he's considered the best character in the game, often placed higher than Pet Shop due to high damage, long combos, and having one of the best traps/setup tool in the game.
Bloodstained
Castlevania
Haunted Castle
Belmont (Simon Belmont)
"Stupid people can believe in anything, so you can believe in yourself!"
Young Joseph Joestar (JoJo's Bizarre Adventure: Heritage for the Future)
"Kumiho unleashed!"
White Fox
Link
Banned (SoulCalibur II)
Console exclusive character. Kratos in MK9 suffered the same fate alongside "Mega Man" & Pac-Man in Street Fighter X Tekken
S&box
Garry's Mod
Castlevania: Resurrection (Cancelled game for Sega Dreamcast)
Belmont (Sonia Belmont & Victor Belmont)
"I'm not used to long-range bouts. You should have won."
Potemkin (Guilty Gear: The Missing Link)
"That's some bad luck!"
Black Cat
Jackie Chan
Legal
There are three different versions of him playable in the arcade game: Jackie Chan in Fists of Fire. All of them are perfectly legal
BioShock
System Shock 2