I'll be able to plot more when I'm home, but young, cute, grumpy, tsundere Victorian magical boy monster hunter Santa is available for all your holiday needs.
Bad Vibes Only
: His name is Noël, (because he's ridiculously uncreative and decided to rename himself after he became Santa) and the manga he's from is both v short and v obscure, it seems. He fights monsters because it's Santa's duty to protect children, and unhappy children are generally monsters' favorite meal.
He is fun! Not a super complex character, TBH, so easy to just get into and enjoy for how gimmicky he is. He's really just a good, sweet kid who suffered a big loss/trauma he can't move on from, so now he's prickly and bitter and tries to hold everyone at arm's length.
His specific loss/trauma is that he didn't believe the hot bishie human form of Rudolph telling him "Hey you inherited Santa's magic power so monsters are gonna wreck your shit until you actually Own This Bullshit and unlock your true power to be able to kill them" until it was too late, and they killed his Sad Innocent Crippled Baby Brother Morality Pet.
The monster was like "LOL let me kill you/take your power, and I'll give you the cure to save him." He was about to go "Yeah okay just murder the shit out of me." until he was convinced otherwise, but the cure was an illusion all along, so L-LOL despair event horizon. Monster got to taunt him in its final moments and cause a breakdown.
Said backstory is four chapters long, but him as the Santa he is now is just a vignette, only about 40 pages long. So if you wanna know about this pain in the ass for better plotting.....
I'd have to make a headcanon judgment about if there are skelly monsters, the canon's only shown snowmen-ish type shit, evil clowns, and those. Although technically the first two are the same thing, I guess.....
Jack offering to give this Santa the year off, see he still has his Santa suit, and with so many Santas who would notice if one took the Christmas off?
PUNCH HIMPINCH HIS CHEEK