This is a great thread :happy:
I've pretty recently discovered the Fenris romance. I haven't played DA2 in years after my initial disappointment with the game where I pretty much hated everything about it after my first disastrous playthrough where Carver died in the deep roads, I was ninjamanced by Merril, I failed to romance Anders as I intended (not sure how that happened) and where I didn't bother to recruit Fenris because I thought he looked too much like an annoying JRPG character.
After a few replays I'm warming up to the game, though, and I'm sold on Fenris and his romance arc. And I love the bickering between him and Anders.
So far, I've only rivalmanced Fenris because I'm very pro-mage and it's just easier to gain rivalry points with him then. I really like the fact that I can disagree with an NPC without him feeling the need to leave the group, and there's a really nice tension between Hawke and Fenris in the rivalmance, I think.
Also, I love it when he curses at me in Tevinter
I've just started a playthrough where I'm going for the friendlymance, from what I've seen on Youtube that one's really good too.