While I would like more with Lycanroc*, this seems like a bad fit. The description is VERY different from Rockruff, so it would have to be a regional variant, and that would make things needlessly more complex.
It sounds like Zorua, but I agree with DrPumpkinz, any regional form would just be a downgrade of a very unique mon.
Dogs/Cats/Foxes that are possible but haven't been discussed much
Yamper: The base form fits, and there's plenty of type combos that could produce that color scheme, but Boltund being what kills the guy, and it being a Gen VIII mon, doesn't seem likely.
Poochyena: The evo still doesn't fit. He also specifically mentions a tail, which is non-prominent on this mon. That said, this line has been due for a rework for a while, so I wouldn't rule it out.
Furfrou: Wouldn't even need a regional variant, just a new haircut. That said, it would be something unrelated that kills the guy at the end. Possible only because it fits TPC being trolls.
Lillipup: Maybe? Regional Stoutland crushing someone makes sense, at least. I can't think of an argument against it, but that doesn't make it likely.
Nickit: Doubtful. Again, it's Gen VIII, and the end of the vid is a stretch.
Skitty: Seems like a good fit, honestly. Design works. Again, the evo doesn't make sense.
Glameow: Gen IV mon getting a regional wouldn't make a lot of sense. And the evo being murderous is odd. Unlikely.
Purrloin: Design is possible, but a stretch, and Liepard is not a murderous beast.
Litleo: I could see it. I'm not sure what typing they'd do, but there's ways to make it work.
Shinx: Same as everything else, possible, but the evo is a stretch.
Meowth: Please god not more attention to this thing. Also, it doesn't fit at all. It's definitely Meowth.
Absol: ...They'd have to give it a pre-evo, but this makes a bunch of sense. It's out there, but I could see a pre-evo and then Mama Bad Luck murdering someone with a cave-in
Animal mons I ignored for being not an option or a bad fit: Eelektrike, Eevee, Snubbull, Houndour, Riolu, Smeargle, Legendary Beasts, Espurr, plenty of other legends/starters/etc.
So my thoughts? Safest bet is that this is a Perrserker situation, the base form is something we recognize, the evolution is completely different. Or that the mon described in the beginning and what kills the guy are unrelated. The evolved forms of too many of the possibilities just don't work for this. If it IS an existing pair, I'd say Lillipup/Stoutland or Litleo/Pyroar are the reasonable options. Outside chance of Poochyena.
Of course, I did all this, so it's going to end up being a regional Nidoran variant or something.
*Just make a dawn form, then make it's evolution purely time based, eliminating the Event-only gimmick for Dusk
Edit: Fun fact, wrapping : : around a pokemon's name inserts the sprite even if you have a line break between them, and it eliminates the line break. I did not know that.