Here's one of the most difficult enemies in the game - devilishly fast, dealing huge damage and controlling electricity. You definitely need all the help you can get against electric attacks. The boss can be found at the very end of Vah Naboris. The fight consists of three stages.
The enemy uses two basic attacks - hovering in the air and flinging balls of electricity at Link, and a quick series of teleportations combined with very quick attacks. The former is pretty easy to avoid. The latter is very efficient and deals great damage. If you have good shields then just block these attacks. It's a safe, albeit time-consuming method. A better solution is parrying the attack with Perfect Guard, or dodging in the last possible moment, which will allow performing a quick counterattack. This method requires some practice, but is very effective.
After losing more than half of his HPs, the enemy will levitate high above you and start flinging thunderbolts. You have to quickly hide behind one of the columns (underneath the platform), chose the magnet rune and raise one of the metal objects from the floor. Raise it as high as the boss is and get it pretty close to him, so that the boss himself gets shocked and falls on the floor. When that happens, approach him, and take some more HPs from him. This will lead to stage three.
This stage is identical to the first one. The boss will attack in the same ways, the only difference being he's attacks are now charged with electricity. If you will try to deflect these attacks with a metal shield, you will get shocked and drop your arms. The best solution now is to parry/dodge and quickly counterattack. The enemy will also start firing a red laser - don't play hero and just avoid these.