Instructions
Visit the store in Pokke where you must buy plenty of Thawer items and Hot Chocolate to keep your character healthy in the hostile conditions where Kushala Daora is found. Pack as many Flash Bombs as your inventory or budget will allow. Put on armour with a wind-protection effect, then set off into the Snowy Mountains to confront Kushala Daora.
Throw Flash Bombs at Kushala Daora when it attacks you. These will temporarily disable its wind cloak. Ranged poison weapons such as a bow or blowgun are also effective. Use either weapon to stun the dragon so it falls to the earth, temporarily incapacitated.
Focus attacks on the crest on Kushala Daora's head. When this has been broken, use cut attacks on the dragon's tail. When these two areas have reached full damage, the dragon's wind cloak will be permanently disabled.
Strike the dragon out of the sky with a long melee weapon, such as a Thunder Longsword, Dragon Longsword, or the Eternal Strife lancet. These long-reach weapons will let you down the beast long enough to get some good strikes on its body. Be conservative with these attacks because the wounded Kushala Daora will still hit you hard if you stay close for too long.
Repeat the pattern of striking the dragon out of the air then unleashing a barrage of ground attacks until Kushala Daora stays down. If you don't kill it in 25 minutes, it will escape, but you'll get another chance later in the game. Use the same strategy for your second encounter and the beast will be defeated.