Monster Hunter: World - 10 Hardest Monsters (And How To Beat Them)

As far as Elder Dragons go, Vaal Hazak doesn't hold a candle to the likes of Nergigante or Teostra (we'll get to them) on the difficulty spectrum, but ignore the title at your peril.

Recall the health-draining Effluvium pollution problem that was plaguing the Rotten Vale on your previous visit. As it turns happens, your new target is responsible for the blight, and has no intention of stopping the leak. He can't; the pestilent mist seeps out of the decaying dragon's very pores, only now, in such close proximity, the pungent odour will do much more than sap your vitality.

Should you get caught in Hazak's breath, it'll slice your health bar in two and only give you one half back. That's extremely not good for obvious reasons, but there's a way to offset the troublesome affliction:

Nulberries!

That's right, the little blue fruit you've relied on so heavily in past battles will work just as well here. Popping one will extend your health gauge back to its normal length, although it won't immunize you against the threat, so bring plenty of reserves.

Along with that gimmick, you'll still have to deal with the slow health drain that occurs just from being in close proximity to Hazak, but keep one eye always on the green and you should be fine.