Four Horns(Diablos and Black Diablos)

I recommend you in getting the full tigrex set, then jewel it for quick eating and i think high grade earplug and auto tracker.

Also try to upgrade the devil slicer to true devil slicer(if you can). But you would want to get a ice weapon, because Diablos are weak to ice not thunder. At your level I would use Blango decimator with 627 attack and 250 ice damage.

Carry lots of flashbombs, shock traps and and bombs if you want to. Bring material to make of the items.

Next carry power armor charms and talons. You can also bring alot power and armour seeds.

If you want, you can bring Combo books 1-3.

NOTE: If you have earplug as an activated skill, it will not save you from diablos scream. You need High grade earplugs.

Fighting strategy

Stay close to Diablos, you should attack its tail, neck and its wings. Oh and if you poison black diablos, it will do alot of damage to him.

When fighting, you should make it get stuck with its horns in a boulder/ big rock, you can do this my making it charge into a big rock/boulder. When he gets stuck you can do alot of things. You can set your traps, combine items, heal and more importantly break his horns or deal alot of damage.

When he get angry, be careful. that is very fast. This is your time to throw a flash bomb and stop his movements. Lay a shock trap, spam damage on him and when he snaps out of confusion, lead him into the trap and lay bombs and blow em up/ or attack him like hell.

Just repeat this steps and you will end up with two dead diablos.

NB: Make sure you get high grade earplug, bring 10 mega potion and potions, as well as max potions two of them in case you die.

Good luck

at your level you should be able to get a good pellet up gunner armour (I think one or a combination of the prey armours - giaprey/genprey/velociprey). Then get the best LBG at your level with the most clips of pellet ammunition. Forget about pellet lvl 3 (too much recoil for a gun without weak recoil - don't think there's an option at your level). I think tail string+ at your level should do the trick.

Then all you need to do is fire off shots at blos's tail. just dodge passed his charges and keep firing off into it's tail - land burrows shouldn't harm you if you know how/when to move.

You do know how to dodge its land burrows right? No? Well blos will always come out of the position you were standing exactly when ALL of it has burrowed underground - so just wait for it to complete burrowing (right until its tail has gone under) then move a bit to the side and get in position to continue firing its tail - don't bring a cat unless you know what you're doing because it may resurface at your cat's location which could make its movements unpredictable unless you know what you're doing. You really will be amazed at how quickly you kill them.

I personally hated using LS against the blos. But if that's what you're sticking with then I'd recommend the blango decimator as well. It's a nice ice LS.
Definitely bring some flash bombs, they help when you're having problems getting them to stay out of the sand. The reason I would lose and run out of time on that stupid mission is because they're keep burrowing before I can get a good deal of attacks in. -.-

Personally, against blos I like to use HBG and pellet shot the tails until they die, really doesn't take too long. :3 Just need a good dodging armor set.

I had trouble, too with that quest. I had a help forum on this recently. I suggest you use a greatsword for the blocks. Just be careful and vigilant when you see it about to attack, and shield.

For that quest, I used Rathalos Soul....
Just gem it for HGE, the Attack up (Medium) should give a nice boost.
since you use LS, like me, use Blango Decimator(it's the best ice LS at 6*)
One tip: NEVER fight them together...and don't forget hot drinks(it's night in the desert)

quote werdna777777

Dude, use any water type weapon=diablos weakness.

Diablos is weakest to ice, twice compared to water

gunner should be easier.
Take a good pellet gun. If this is a low rank one, there aren't many good pellet gun. Just take a bowgun with good pellet clip and shot diablos tail.
the pellet will automaticly target it's tail (it's weak point).
With low/high rank, diablos burrow attack will only target the place where you (or your cat) are when it enter the ground. just move to left or right and you will be safe.
it is advisable to carry a lbg if you can't dodge it's charge with Hbg...

the roar? use HGE aromor if you scared of it too much, or else just keep your HP max so that you won't be OHKO by him

not sure about bow.... I prefer bowgun ing diablos...