A real oxymoron, Skel is a buff skeleton. Due to being reanimated a few years ago, he's a bit out of the loop about the current state of the world. However, he's a gentle soul. Harmless, given you aren't robbing him. He takes pride in the general store he runs and enjoys the simple life he lives.
So for a bit of context as to how skeletons work in my mind, Necromancers exist and at this point in time don't do a whole lot on the grand scheme of things. Most of the time nowadays, when they ressurect a skeleton it's to do some petty chore, only to send the skeleton off to society right after. Skeletons are fairly impressionable right out of the grave. Along with that, skeletons remember almost everything about when they were alive MINUS any specific people or names. If they were a pro skateboarder when they died then they can still hop on a board and hit that kickflip, but they don't remember their own name.
Now Skel falls into that "resurrected to do a chore" storyline, a necromancer revived him and pulled him into his lab. He had this big machine he needed moved to another side of the room for Feng shui reasons, and the last few times he's used magic to move things himself they got thrown out windows, so he doesn't want that to happen again. The plan was to get the ingredients to cast a strength spell onto Skel and get him to move it. The necromancer had never done this before, he kinda just expected a normal ass skeleton who happened to be able to lift 500lb of machinery. He casts the spell, and after a brief moment, Skel was huge. After a moment for both parties to comprehend what just happen, the necromancer awkwardly got Skel to move the thing and then leave.
Usually, spells like that are temporary. In fact, that strength spell that was used is expected to last for about two or so hours before wearing off. But skeletons are a little less predictable. Their life force is the mana that they were resurrected with. On some rare instances, temporary spells like this can stick around way longer, sometimes permanently. After the two hour mark, Skel was a bit less swollen, but it was clear he was kinda stuck like this.
Now thrown back into society, Skel did a bunch of odd jobs around a few different towns for about a year to make ends meet. Once he got a decent amount of cash, he got ahold of a building which he decided he wanted to be a general store. After setting up the store for a while, Skel recieved a bunch of packages to his store. He didn't order anything. Hell, I don't think he knew delivery was a thing. There was a note attached, welcoming him to the shopkeeper's guild and that he would recieve stock when needed. Inside these boxes, there was a good 60% of what you would expect a general store to sell, but the other 40% seemed to be entirely random. Food to electronics, toys to hygiene products, even potions and weapons. Skel was confused as to how a "shopkeeper's guild" even knew about him, but free stock is free stock. Because of this, you never know what could be in Skel's shop, and that's what entices most repeat customers. Plus, Skel has the tendency to mark down anything he doesn't know what it is.