I know what you're thinking, Stitch!Sans? Really?

Well...he's more important than you think.

He's an out!code character, meaning he doesn't exist in any timeline, and is very important to the world overall. 

He dwells in a place known to him as the TimeSpace Timeline, which looks a lot like space, except each star is a small crystal ball representing a timeline. A large crystal ball is the centre Timeline, a place if found would lead to any other timeline in that set universe. Timeline crystal balls have to be kept close to the centre Timeline for it to be recognised by Stitch!Sans as part of the whole Universe.

He makes sure that the Universe's timelines (regular Undertale or any Alternate Universe) are all tied together in one way. He also has to make sure that all timelines for one universe are all linked.

Why?

Well, if a timeline weren't tied to another of the same Universe, it would float away. If it floated far away, the results would be disastrous for the said time,one. If it floated into another Universe's set of timelines, they would merge and there would be a large rip in the fabric of space and time.

So, how does Stitch!Sans keep the timelines together?

Needle and thread.

He literally makes links between the timelines, keeping them together, using his needles and thread. Sometimes the threads break and Stitch!Sans has to replace them. If the fabric of space and time is ripped he has to stitch that up too, at the cost of some of his health.

This being said, he can't change anything in a Timeline or kill anyone otherwise there would be a rip in the fabric of space and time. He doesn't create Timelines, Universes or characters. He doesn't destroy them.

(Anyone familiar with Ink!Sans or Error!Sans would know that they create/destroy)

But of course, the number one priority is the Centre Universe, Undertale itself, and all timelines within it, because just as Undertale sparked the creation of every Alternate Universe, it could also take the Alternate Universes away if something bad happened to it.

Stitch!Sans can float around in the TimeSpace Timeline and teleport if needed, but not too far.

He has a small amount of magic compared to any other Sans and only one Gaster Blaster. 

As for his appearance, Stitch!Sans is slightly taller and thinner than Undertale Sans. He has a brown jacket (without a hoodie) and a black bandanna he wears around his neck. He wears dark brown shorts and black shoes. Yes, shoes. Not slippers. He has a sheath on his brown cream-coloured belt for his needles and a strap going diagonally around his shoulder and body with little pockets in it where he keeps his thread. His left pupil is a clock (the hands change places when he blinks) and his right pupil is the normal white colour.

As for his personality...he's pretty laid back, but loves all Alternate Universes except for the smutty ones (like Undertail and Underlust. Don't search them up, kids). He likes to watch major events through the crystal ball Timelines but gets bored easily. If he met anyone he would be pretty kind. He gets lonely sometimes and the Gaster Blaster, seeing as it doesn't have a personality, doesn't make him feel any less lonely.

Random facts about Stitch!Sans:

. His favourite Alternate Universes are Underswap, Candytale and Outertale

. Sometimes he likes to make dolls but then he loses them when he gets bored and they float away

. For some reason his thread will regenerate

. If he met Error!Sans things would go badly (I don't have Tumblr so I have no way of contacting Error!Sans' owner to make this dream come true)

(Wow this is my favourite OC yet I should make a story about him)