BEAT DIABLOS FUCKER
I learned all his attack motions and through trial & error a bit figure out when I could get 1-3 swings of my hammer in after most of them. So I'd do a few hits and then roll out of the way, wait for his next attack, dodge, go in for 1-3 hits, etc... also using environment as much as possible and any stuns I can. I thought I was doing ok, blew through so many healing items but hadn't fainted. Then the 10 mins remaining message popped and I was like shit shit shit shit as Diablos had only just started limping a bit before that. So at that point I just said fuck it, DO OR DIE TIME and I started going in with non-stopped charge hammer blows trying to dodge and stick to his face and luckily I kept smacking him and only got hit once and recovered. Killed him in about 4 mins of that all attack frenzy. Total time was 44 mins.
Got a body armor piece so DEF is up to 123 with +8 fire def which should help for Rathalos. Problem is that he's a fire dragon and my rarity 3 hammer with 780 attack I've been using on all these guys is Ajangath fire element, so it'll probably do bad damage against him. Considering I expect it to take like 44 mins as well, I need to gear up on my weapon before the fight. Time to fight Jura-whatever-water dino a bunch of times and build up my rarity 4 aqua hammer. It only does 680 damage but has like 230 water as well and he'll probably be weak against water. So yeah, gonna grind out that hammer next time and then go for Rathalos.
The problem with Diablos, besides just being a prick is that if you're in his face you need to roll to get out before he does a charge but if you roll a direction he is charging you get hit. Not sure if there's a safe method like roll towards his tail or something. I just tried to roll out early enough to dodge the charge. Also got the hang of dodging while getting up and roll roll roll quickly to gtfo before he charges into where you were knocked down.