I don't think any class does as much damage to World Boss as Fire main does (with the current ninjas). If you don't have Iruka, you run into the problem of, if he does Exploding Hell, you lose the WB Asuma buff. To counteract this you can run Guy instead (gives Taijutsu buff, life leech, and his kick hits for quite a bit too).

You don't want to stay alive after the Tailed Beast Bomb because your damage-per-minute falls off. Here is my lineup: Scarlet Blaze Guide