It seems a lot of people (including me at first) have enormous problems fighting the Tempered Kirin;
The fight turns out to be pretty easy if not cheesy once you use a light bowgun and slicing ammo (even after the nerv :O). Simply craft one and push reload mods so you can reload while walking.
Do the Quest solo.
Once you push enough dmg and he returns to the most top part of the map the fight is basically won with every weapon: Get up there, drop 2 Mega Barrel bombs (Wyvernshot if you can), set him ablaze and then simply jump off the ledge -> Return to camp and restock the bombs. As soon as you enter the tent you evaded the monster, he returns to his 'nest' and you can rinse and repeat with the bombs.
Works on every difficulty and turns the fight into cheese.