Tu Ka'loh is a character from The Legend of Zelda: Breath of the Wild. He is a Sheikah Monk serving the Goddess Hylia and guarding the Tu Ka'loh Shrine's treasure, a Spirit Orb. He offers the trial "Tu Ka'loh's Blessing". He is also apparently the mysterious voice responsible for giving Link the Shrine Quest "Trial of the Labyrinth" which involves navigating Lomei Labyrinth Island in the Akkala Sea region which acts as Mini-dungeon that Link must navigate to reach his Shrine.
It is implied that Tu Ka'loh was involved with the construction of the artificial island and its labyrinth. Additionally the labyrinth contains many pieces of Sheikah technology from Guardian, Ancient Materials, and the Travel Medallion implying he may have been some kind of ancient engineer which would be fitting as the Guardian researcher Robbie lives nearby in Deep Akkala and is a capable engineer in his own right as he has reverse engineered ancient Sheikah technology to create Anti-Calamity armaments.