The Monk Maz Koshia is a Sheikah as well as a boss in The Legend of Zelda: Breath of the Wild. He is fought at the end of the Final Trial as the last trial before being rewarded with the Master Cycle Zero. He is a Sheikah Monk who is tasked with testing those who want to pilot a Divine Beast.
He first speaks to Link inside the Shrine of Resurrection, where he bestows the One-Hit Obliterator to him as the first part of his Trial. He informs Link that to complete this part of the Trial, he must travel to the four marked locations on the Great Plateau and defeat the bands of enemies there. After Link has accomplished his task, Monk Maz Koshia will congratulate Link on his progress and reveal that this task was only the first. The Monk continues, saying that the One-Hit Obliterator will guide him to the next steps. This causes the One-Hit Obliterator to split into four glowing orbs, which scatter to various parts of Hyrule. Monk Maz Koshia urges Link to follow them in order to continue.
After having accomplished the four quests related to the Champions, Maz Koshia will call to Link once more, instructing him to return to the Shrine of Resurrection to face the final trial. Once Link returns to the Shrine of Resurrection, Monk Maz Koshia will greet Link and tell him to return the Sheikah Slate to the terminal he found it in to reveal the passageway to his final trial.
Once Link has reached the end of the Final Trial, Monk Maz Koshia stands up and teleports the two of them away to a platform in the sky, where he challenge the hero to a fight. Once Monk Maz Koshia is defeated, he will shrink back to his normal size and congratulate Link for overcoming all obstacles he could conceive. Afterwards, Monk Maz Koshia will activate the flying structure that they are on, causing the Master Cycle Zero to rise from within. Monk Maz Koshia explains that the Master Cycle Zero is a masterpiece of innovation that was intended for the "one true hero." With his role served, Monk Maz Koshia wishes Link well before returning him to the Great Plateau.
Like a Yiga Footsoldier, Monk Maz Koshia can magically teleport and strike Link from above with his Sword, or he may use a Bow and shoot at Link from the air. Monk Maz Koshia can use Fire Arrows, Ice Arrows, and Shock Arrows to strike Link. After Monk Maz Koshia's health has been reduced by 25%, he will retreat and split himself into nine copies. Each of these copies can damage Link, though only one of them can sustain more than one hit. In order to advance, Link must find the correct copy of Monk Maz Koshia and attack him. The copies can work together to strike Link in unison with arrows or their blades.
Once Monk Maz Koshia's health has been reduced to half, he will retreat again and magically enlarge himself while flying in the air. At this stage, Monk Maz Koshia can use charged laser attacks to strike Link. If Link deflects one of these lasers back at Monk Maz Koshia, the Monk will be temporarily stunned, allowing Link to attack him multiple times. Monk Maz Koshia may also summon a series of eight metallic, spiky balls that he will toss at Link to hurt him. Afterwards, Monk Maz Koshia will begin charging a lightning storm, which will strike each of the metallic balls. Link can use Magnesis to direct one of the metallic balls near Monk Maz Koshia, causing him to be struck by his own Lightning, which will stun the Monk.
Monk Maz Koshia can also magically tilt the battle stage before summoning the metallic balls, which will roll towards the bottom of the slope before falling off. Monk Maz Koshia can also stomp the ground to cause a tornado to chase Link around. If Link is hit by the tornado, he will be struck by a strong pulse from the ground. At some point, Link can ground Monk Maz Koshia. If Link gets close to Monk Maz Koshia's feet, the Monk will stomp the ground, the shockwave generated by the shock will damage Link if he stay too close. Monk Maz Koshia can also summon two miniature copies of himself, who will attack Link in a similar manner to the second phase of the fight. Like the Yiga Clan members,Maz Koshia can be distracted once during the fight by laying Mighty Bananas on the ground.
Hyrule Compendium Entry
"The arbiter of worthiness for the hero who wishes to control a Divine Beast, following a revelation from the Goddess Hylia. As the last part of the final trial, the monk offers a challenge of ancient techniques."
- Since Maz Koshia is an ancient Sheikah Monk, he is over 10100 years old in Breath of the Wild.