This gif comes from footage of the dwarf boot camp, of course. That is Jed Brophy, a.k.a. Nori, on the right, Peter Hambleton, a.k.a. Gloin, in the middle, and that is Adam Brown, a.k.a Ori, doing... well, doing whatever he is doing here.
Looks fun, though.
I love how Peter is taking it all so seriously while Jed and Adam are just having a blast. XD