Yunobo is a character in The Legend of Zelda: Breath of the Wild. He is a Goron living in Goron City in the Eldin region of Hyrule. Yunobo is also a descendant of Daruk, the Goron Champion who fought along Link 100 years before the events of the game and as such he has inherited the ability to use Daruk's Protection.
For the moment Yunobo's role in the Zelda series is only composed of informations with an unconfirmed timeline placement and should stay this way until we have a definitive answer, so please don't add any information regarding the timeline placement without OFFICIAL confirmation, thanks.
Before he encountered Link, Yunobo is said to have helped Buldo fighting back the Divine Beast Vah Rudania but it is only after his teaming with Link that the duo are able to fight the Divine Beast back. Once Link succeed in freeing the Divine Beast, Yunobo is able to see his ancestor while the Divine Beast is heading to its firing position.