The Official Monster Hunter 3 Ultimate Topic

Deviljho is pretty scary when you first see him, but he's actually really easy as a blademaster. Just stick by his legs. You take more damage running around like a headless chicken trying to avoid his attacks then if you just stick close/under him. Most of his attacks involve him twisting and lunging forward, while he only has one or two very telltale attacks that can hit you when you're at his legs.

Yeah, pretty much this. One of my friends used to dodge most of Deviljho's attacks on Tri just by walking through them, and he says it's really not much different for 3U in terms of how easy it is to avoid.

For me, Deviljho is about like Barioth was in Tri, in that I can just roll into nearly all of his attacks with Evasion +1.