Edgelord is quite an interesting character lore-wise. I promise! I know he's got a dumb name but in my defence, he started as a Silvally and I always nickname those Edgelord because. I mean look at them. What else am I supposed to do?
He's the artificially created son of Mitzy and Funnybones. Mostly Funnybones, she was the one who actually put him together from scrap parts she had around the lab (or could source on a time crunch...) The multiple formes (yes I'm going to spell that with an 'e' like pre-gen 7 Pokemon) don't really have an explanation, other than that I made the bipedal one first, didn't like it, and then made the centaur-body plan version which I have now decided is the canon one.