Undertale OC Wiki

"Wowie, that sure hurt, mister. Don't you know it's dangerous to have stuff like that just while walking around? That's alright if you didn't know, sometimes I don't know I do dangerous things either, and I just tell Sansy that I'm sorry afterward. I'll accept your apology, Mr. Human, cause you and your sister were so nice to me before so I know it wasn't on purpose!"
– Serif after the first hit on the Genocide route

Bree Serif (Serif for short) Is a OC Created by Gracie11facie. She is the little sister of Sans and Papyrus in the AU, Underkin. She’s a small female skeleton with a lot of personality, who is usually seen with a magnet bow on her skull and a galaxy scarf also tied into a bow



Serif has a number of physical characteristics that stay constant:

  • A purple Gaster Eye that always glows, though she is usually harmless.
  • A sizeable crack in her skull going over her right eye, causing an inability to open that eye
  • A magnet embedded on the left side of her skull

She also has a few characteristics that are added as part of her daily routine:

  • Black "Freckles" drawn on with magic marker
  • A bow or other "hair clip" style accessory attached magnetically to her head
  • A galaxy scarf tied in the shape of a bow

Her usual outfit, or at least the one the PCs see her in upon first meeting, consists of a gray sweater, blue skirt, black leggings, and red boots, along with a purple bow to match her iconic galaxy bow/scarf.


Serif is an excitable young monster, and will give fast-paced, long-winded speeches about her brothers with little to no prompting. She often says that Papyrus is her hero, but if asked who her favorite brother is she will ask if you are joking, saying she couldn't possibly pick just one.

Her personality is more like Papyrus than Sans. She is very determined and will try her hardest at everything, whether it's helping Papyrus make spaghetti or standing watch for Sans while he sleeps on his shift. She is a huge fan of word searches and other puzzles, always insisting on trying out Papyrus' puzzles first.

Serif doesn't like to fight, and in fact hardly knows how to. In the genocide run, if you try to kill Serif before her brothers, she will not attack, as she just assumes innocently that you are having a pleasant conversation. When you then strike her, she becomes confused, but assumes it was an accident and says she forgives you. The second strike makes her cry, and she asks why you are hitting her, and the third strike will kill her.


Sans and Papyrus

Sans and Papyrus are her big brothers, and they haven't told her anything about Gaster other than the fact that he was their father. She loves both her brothers immensely and will give long-winded speeches about them to anyone who will listen.

Papyrus is her morning routine helper, as Sans almost always sleeps in, so her bow/scarf is always tied lovingly by hand by the taller skeleton. He helps her put her boots on, packs her favorite spaghetti, and walks her to school. When he gets home, he has her help with dinner while she talks about her day, listening closely to every detail. If she has any school events, both brothers will be there, but Papyrus always puts in the extra mile, even convincing Undyne to come down for career day for her. They always do some kind of workout after dinner together, but usually not before he races to Grillby's with her on his shoulders to deliver dinner to Sans.

Sans picks her up from school, even though he's supposed to be at his post. He always abandons his shift to hang out with her at home if he can get away with it. He'll usually tune out her ramblings about her day to a point (He somehow always remembers it all afterward, even though he definitely isn't listening) and set her up to do some arts and crafts. Sometimes he will join her, usually a day or two after he notices she is running out of magnetic "Hair clips", and he will make new ones by hand. He leaves for his shift at Grillby's around the time Papyrus comes home, and gets home just in time to tuck her into bed. Serif cherishes these bedtimes because Sans always tells her grand stories about alternate worlds.

Other monster kids

Serif doesn't care for other monsters her age. She only ever got along with Asriel, but then he stopped coming to school and his mom wouldn't answer her questions. She has known Alphys' twin siblings since she could remember, since Alphys and Sans are friends. She likes MK just fine, but his twin sister (Name TBD) is too gossipy and rude for her taste. Since they are basically inseperable, she doesn't really hang out with them.

Frisk and Frosch

The PCs, Frisk and Frosch, can easily befriend the little skeleton girl in the pacifist run by agreeing that her brothers are the coolest and listening to her whole story without walking away. She develops a small crush on Frosch after his performance on Mettaton's show, and gets embarrassed when talking directly to him.

They are not friends in the genocide route, but you can still choose to mercy her at any time if you are fighting her first.