* Golly, this sure is terrible
To meet the UTAUWiki's article standards, this article requires proper grammar and/or proper wiki structuring. Please help by improving the article.
Sans is the Head of The Autumnfall Guard Unit. He is extremely lazy, but occasionally hard working. He is Mostly passive-aggressive towards Frisk, but will still try to capture them in the end. Sometimes, he will help out with Gaster's experiments. If he didn't make a promise to Toriel, Frisk would be dead.
His arms are folded behind his back and is standing up straight. He wears a blue jacket around his waist and a pair of goggles. He also wears a grey sweater with white sleeves and yellow patches with bones on them. One on each arm and one where his heart should/would be (Toriel made the sweater for him). He wears black sweatpants with one yellow stripe going down (Like Fell Sans). He wears blue boots.
When he isn't on guard duty he is seen wearing his jacket and has his goggles on his neck. The rest of his outfit is the same.
He is a lazy guy. He spends his time off guard duty watching Lady Otaku, sleeping, or selling hot dogs. He loves ketchup and Toriel sometimes bribes him with it when he refuses to do stuff. He loves puns a lot and sometimes goes to L.O's Kawaii Club for stand up comedy. Despite being chill and lazy he is very cunning and is well known for his ingenious tactics.
(If you plan on making some of these characters into wiki articles read the main story on the AUs wiki page and do it when their arc is done. Make sure to not insert fake information or an assumption of what will happen in the story.)
Twisted Storyline! Frisk (Depends)
When Sans met Frisk for the first time he was extremely disappointed that he couldn't end the kid's life and take their soul to Queen Undyne. But as Frisk progressed he saw the kindness they showed to others and "threw em a bone" later on in the story. Of course, he still helps his brother, but he tries to help Frisk as well.
No confirmed relationship
Twisted Storyline! Papyrus (Brother)
Papyrus is the younger brother of Sans. Just like Undertale Sans, Sans doesn't want anything bad to happen to his brother. If you spare Sans but kill Papyrus later on, Sans will not be seen for the rest of the game. If you still have to do the hangout with Sans he won't be outside to let you in. And if you try to go inside the doors will be locked. Their relationship is quite distanced due to their work. They both want things to go back to normal when Sans always annoyed Papyrus by cracking too many jokes, or watching a Mettaton and Napstablook concert on TV. Fortunately, Frisk came by and fixed their brotherly relationship......By burning Papyrus' house down.
Twisted Storyline! Toriel (Best friend)
Toriel is Sans' best friend. Ever since they were 7 years old they were inseparable. Toriel was Sans's second friend he ever made. They grew up by each other's side. Sans even tried to help Toriel get a date with Prince Asgore when she was going through a pretty crazy phase. Of course it didn't work but this proves he cares about his best friend. They love telling puns and knock knock jokes to each other. Sans was going through a state of depression after Papyrus moved out, So Toriel moved in with Sans and they became roomies. (They never did and don't have a romantic relationship. But you can ship em if you like I don't care I am Soriel trash too.)
Twisted Storyline! Gaster (Father)
Gaster is Sans's father. Their relationship is like your average father and son. Sans will occasionally help Gaster and Alphys with experiments (sometimes being paid) making him somewhat his employee. If Sans is killed in a Neutral Run Gaster will not be very friendly and will say "I would kill you where you stand if someone wasn't already on the way." He would also say this if you did a neutral run and killed Papyrus or killed both Sans and Papyrus. In a nutshell, he cares a lot about his sons.
Twisted Storyline! Alphys (Friend)
Alphys is a friend of Sans. Their relationship isn't too special. They work together on many experiments. Sans helped Alphys build a mech suit that would become the Mettaton of this AU. He encourages Alphys to be open about their feelings to Undyne.
Spectral is Sans' grandfather. Sans doesn't remember much about Spectral because he had died when Sans was at a young age. Sans looks up to him from the things he has heard about him and will sometimes go to The Hall of Legends and talk to the Statue of Spectral.
Twisted Storyline! Flowey (Rival)
Sans and Flowey hate each other. They are always at each other's throats. Sans has caused Flowey a fair share of resets. Flowey calls Sans a "Smiley Potato Sack." They will end up having arguments or full on death battles, depending on the timeline.
Twisted Storyline! Grillby (Friend)
Sans and Grillby's relationship doesn't really change. Grillby was Sans' first friend. They always got bullied for what made them different, which made them stick together. Sans will come to Grillby's sometimes, order his daily ketchup bottle, and just talk to Grillby. Sans' nickname for Grillby is Grillbz.
Twisted Storyline! Muffet (Possible Girlfriend)
Though it is not confirmed and probably never will be, Muffet might be going out with Sans. They met at L.O's Kawaii Club. From what is known they seem to have taken an interest in each other. They meet up at places sometimes but they aren't confirmed to be dating. (I can assure you I don't really ship Sansfet (Sans x Muffet) but I didn't want Sans to be a pile of lonely bones. Though in the future, I will make a next generation thing and possibly have a Sansfet child.)
(To learn more click on this link to the to the AU wiki page Undertale Twisted Storyline)