Ighty, so the user performs the needed handseals and can set the area, between him and his opponent in fire. Though the best part of this is that, the user chooses the certain area he needs to burn, that is the area where his specified target is standing, or a little summon or clone, stuff like that. And the only downside, is it will take one turn to reach the full temperature, which will burn the enemy's limbs severely.