I'm really doubt it but the character in question is an alter ego of Sombra, Dark Star. Dark Star is the person Sombra was, not the mindless dark cloud that he was in the show. Dark Star isn't evil but is still more than willing than to kill someone. I don't think I need to add more detail but if I have to ask.

1232400

For the most part, I'd say yes. If you consider Sombra as different enough from Dark Star that he constitutes an alter-ego.

It's murky to begin with, though. Background ponies with no canon traits arguably count as OCs (in uniform) when given a personality to suit a fanfic writer's needs.

1232400
It depends; I did a similar storyline about Sombra before he became evil and in that story it was clear that Sombra and the pony he used to be were two seperate personalities. In that case yes Dark Star would be an OC.

1232400 I feel as if it is a non-canon OC. Like Cupcakes Pinkamena.

1232410 The "non-canon OC" thing for "Cupcakes Pinkiamena" kind of dbugs me, because Pinkie in Cupcakes is her bouncy-maned self, but so often I see that persons operated as Pinkamena.

1232479 ((Welp, sorry. I never actually read cupcakes, but I saw the youtube vid, and that was straight mane Pinkamena))

1232496 Oh, okay. Yeah, that vid's inaccurate in terms of Cupcakes. Pinkamena is, however, at least in Party of One, a schizophrenic in canon ( or at least shows signs of it)

1232525 Yeah, I guess, but I'm talking about Cupcakes Pinkamena, not Canon Pinkamena. I feel as if Canon Pinkamena would never do Cupcakes, though it could be just AU

1232547 Yeah, if Cupcakes Pinkamena was Cupcakes-ish in correlation with the established Pinkamena's personality, she'd be depressed while murdering Rainbow, but she's happy instead.

1232400

I think every background pony who was never developed or underdeveloped would count as an OC. But since this Dark Star is a complete offshoot never mentioned in canon, then he definitely is.