So the archangel Gabriel, who has moonlighted as the trickster god Loki, is now being decidedly untrickster-ness. And deciding to stab someone with some magical wooden sword.
He wins, but is injured in the process. So what is prompting the trickster archangel to go all murdery? Well the dead man is Fenrir - one of the sons of Loki. And yes he’s a man but he kind of has a wolf effect to him and big claws so I can kind of see it - but he dies too quickly to develop this massive wolfy-murderer of Odin-ness to us. Gabriel has a list of more people to kill: he crosses off Fenrir leaving Narfi and Sleipnir. That would be two more spawn of Loki.
Injured, he turns to the only people he knows who can help - Sam and Dean (since Sam and Dean are in town following him since he’s still the only source of Archangel Grace they know of). He hoped they may actually have some of his Grace left but they don’t. Which is a shame since after being so tortured and drained by Asmodeus and then frying Asmodeus he is now running on empty which is why he has resorted to stabbing people.
Fenrir’s brothers, Sleipnir and Narfi decide to hunt Gabriel down for their brother being murdered and we have a god fight. And while Dean seems able to fend off a not-really invested Sleipnir but Sam is nearly strangled by Narfi before Gabe stabs him in the back. At which point the horseman flees
And, yeah, ok I’ll buy sort of werewolf Fenrir - but Sleipnir being a dapper prettyboy? I could get behind this is there were some development of Loki’s children instead of it just kind of not wanting to be bothered with CGI or monsters or special effects.
So with two of the brothers dead, Gabriel wants to kill the last one - and then kill Loki. And he explains why in a long exposition that Dean really really really doesn’t care about. Way back when, Gabriel was tired with all the Archangel stuff so he decided to go undercover - he ran into Loki (who owed him after he freed him from his cave where Skadi’s snake was dripping poison into his eyes) who agreed to teach him how to be a trickster and take his identity. Which worked for Loki as he was kind of in the outs with his family anyway and needed to go a little low key
They don’t specify why Loki needed to hide from his family but even a cursory reading of the Eddas says yes yes he does.
And when Gabriel decided to go into hiding AGAIN, because Lucifer was coming in, he decided to turn to his good friend Loki and sons so he could hang out with them. Until they betrayed him, captured him and delivered him over to Kentucky Fried Asmodeus for lots of money and now he wants revenge
And Dean is not impressed. Dean doesn’t think revenge is helpful - because he’s been there and done that over and over. Lots of epic revenge and it never actually made Dean feel better. Also Gabriel’s revenge plan is so theatrical and nonsensical that Dean can’t help but mock its nonsense.