Master Kohga

Master Kohga is a Boss in.

Characteristics
Master Kohga is the Leader of the Yiga Clan, an opposing Clan to the Sheikah Tribe who hunt Link on a ceaseless mission. Master Kohga is a powerful figure of authority, but he behaves in a quirky and peculiar manner.

Link meets Master Kohga during the "Divine Beast Vah Naboris" Main Quest, outside of the exit of the Yiga Clan Hideout in an open area with a large pit in the center. Master Kohga will recognize that Link is the hero he has been searching for and initiate a battle. After defeating Master Kohga, he will use his last bit of energy to perform his "secret technique" which backfires causing him to fall down the large pit in the centre of the battle arena. While falling down the pit, Master Kohga is heard yelling that he shall be remembered and the Yiga Clan will track Link to the ends of Hyrule. As a reward, Link will receive a Treasure Chest containing Riju's Thunder Helm.

Strategy
The fight against Master Kohga consists of three phases, each of which utilize his control over magnetism and levitation. In the first phase, Master Kohga conjures up a rock above him to hurl at Link. Hitting Master Kohga with a ranged weapon, such as Arrows, will break his focus and cause the rock to fall on his head. This temporarily stuns Master Kohga and allows Link to attack him unopposed.

In the second phase, he levitates above the large pit nearby and conjures up two rocks that spin around him. Link must hit Master Kohga when one of the rocks is directly above his head, causing it to once again fall on his head and stun him.

In the third and final phase, he conjures up a fortified boulder to attempt to crush Link. Link must use Magnesis to gain control of the boulder and push it back towards Kohga. This will stun Kohga once again and give Link the opportunity to finish the fight.

Trivia

 * Master Kohga is the only boss in Breath of the Wild that is required to be fought before entering a Divine Beast, Vah Naboris. He is the only main boss who isn't directly connected with Ganon. He is even the only main boss who is complete optional to confront as he wouldn't Hyrule Castle if you didn't defeat him.