That part won't be in the history books, because why would it be? Tyr was the bravest God, he even dared to put his hand in Fenrir's mouth to placate him and lose it if the binding they performed was a trick. Well, he lost that fucker, and Fenrir has been pissed about it ever since. Hence the pouncing to eat in the above gifs.
She blames pretty much 2 people for what happened, her grandfather and Tyr because he lied to her. He, on the other hand -HA-, doesn't seem to hold it against her and seems to find it funny to treat her like nothing ever happened even as she maybe tries to eat him. He just keeps being ok with it, and she keeps not being ok with it and they probably have epic fights and for some reason I see him hitting on her just cause he's him and not afraid of anything like an idiot?
I feel like he's very fighting oriented, always looking for a challenge, and a giant wolf that gets stronger the more you fight it falls squarely into that territory. I feel like him accepting that he was going to lose his hand before he even put it in her mouth kinda means he's not mad, and eventually she could be persuaded to stop being angry at him 24/7, probably tone it down to like 21/6.
I feel like them having to fight a common enemy might make them sort of begrudgingly (on her part) just kind of reach an equilibrium. If it winds up being a ship (provided he doesn't mind she's a wolf and a guy at random) I am so here for it and would prefer that cause it would be hilarious, but also like a good close battle buddy is aces. He'd be an Asgardian, older than fen probably, and his face is Nikolaj please because LOOK AT HIM. What exactly his personality is and what he's been doing is up to you, but you get the idea. Take him please Fen needs someone to be her friend that isn't her boss or her brother, like this girl needs people.