Another one of Ganon's minions awaits at the very end of Vah Rudania. The enemy commands the power of fire, so you should furnish some equipment that can protect you from this element. Eating something and drinking a potion in order to improve your resistance - this fight isn't easy.
The enemy is quite aggressive and will often try to engage in close combat. His main attacks involve a mighty swing with his sword, which are fortunately clearly telegraphed and can be easily avoided hence. Depend on dodges and quick counterattacks. Add to that a powerful bow - hitting him a couple times in the head will stun him eventually, allowing you to reduce the distance and attack with a powerful, double-handed sword. From time to time, when he gets really angry, he will fly up and fling fireballs at Link - these aren't difficult to avoid. If you want to solve this dispute with melee weapons, make sure you're attacking from behind and quickly roll back. After taking 50% of his HP, stage two will commence.
The enemy will start using a new attack - charging a great bomb in the air, while being totally immune to attacks. Soon a as he begins doing that, close in on him, select the bomb rune and throw it at him - it will get sucked along with the energy converged by the boss - detonate it and the enemy will fall on the floor. Attack him again. The procedure will be identical to stage one, except the boss' sword will now be burning, dealing more damage. Attack with melee/ranged weapons and the enemy will soon perish.