Fast learner
An underrated skill of Dagur's in my opinion is one that was mentioned by Fishlegs in "Family on the Edge." He called him a fast learner and he was right. Dagur is an extremely fast learner and an extremely skilled dragon rider when you consider how long he's been doing it vs the others. They have had their dragons since the days of Riders and Defenders of Berk. Dagur's first time even riding a dragon was in season 3 of RTTE, then he got trained in one day at the end of the season. Despite that, he never holds the others back by not being skilled. He fits right in with them like he's had as much time with his dragon as they've had with theirs. Heck, we even see him standing on Shattermaster's back which is a move we've only seen one other character do (a certain Viking who lived with dragons for 20 or so years, so let's really put what he did into perspective).
Even though Heather's had Windshear longer, Dagur and Shattermaster were able to outmaneuver them and get to the shipyard. He came up with brand new moves that Fishlegs hadn't even considered (despite Fishlegs being the Gronckle guy before him). This isn't even just for Shattermaster. Let's also remember that Dagur's had two dragons, so he didn't even get to know Strykie until a later season. Still, he was able to ride without a saddle easily and even get a type of bond where he can whistle, jump off an area, and land right on Sleuther's back (I highly recommend finding that moment from "Searching for Oswald...and Chicken" if you forgot about it because it's so cool).
So, I just want to do a bit of an appreciation post for him with this because it's honestly very impressive. The fact that he specifically trained Sleuther is a feat too. The Triple Stryke was quite evidently one of (if not the most) difficult dragons to train, but Dagur has him and they work perfectly together. That's why I have to give him some major dragon training and riding kudos.