Zelda Ocarina of Time 3D
Zelda Skyward Sword for Wii

Zelda Twilight Princess Walkthrough - Part 18c - Hyrule Castle

Final Boss Form 1 - Puppet

Your enemy will posses one of your close friends, so you must fight them. Pretty much this person floats around shooting balls of energy at you. You must bounce them back with your sword. Your friend will shoot a burning triangle on the ground every now and then, so be QUICK! You must swat the energy back and forth until you hit the puppet a few times. Now you meet the next form of the final boss.

Final Boss Form 2 - Dark Beast
Well, turns out your enemy has a Twilight Beast form too, which is kind of dangerous! Your enemy will run around rampaging the whole place, so try to avoid him for the most part. Eventually he will disappear into a portal, so you must look around for the portal he's going to come out of. Use your bow and shoot him directly in the forehead. After he falls, jump out of the way and then hit the gash on his stomach.

After doing this enough, he eventually gets smart and starts dodging your arrows. You must now turn into your wolf form and use Midna's help to wrangle him (like with the goats). Let him charge at you and press A at just the right time. Move the control stick left or right and then you can attack his stomach again. Eventually you will defeat him.

Midna decides to finish him for you, how wonderful. Eventually you end up sitting on Hyrule Field with your buddy Zelda.