A yamatunga is one of the high preists of the Incoaztec pyramids of the Polombian area of the Amazon Rainforest; spasifically, the Marsupiquatl Pyramid, which is a big deal, because his job is to keep people away from the cursed treasure of Marsupiquatl and, more importantly, the poison stone (he calls it the "Sky Stone", as that toxic rock that threatens the marsupilami existance was once a meteor) that is in a hidden chamber of that pyramid gaurded, otherwise, by boobytraps.
From childhood (traditionally, boyhood), each yamatunga starts out an apprentice to the last one, and learns the sacred ways for, along with the temple, the yamatunga's job is protecting the very creature made sacred their... the marsupilamis themselves! Along with a feathered headdress for statis, the yamatunga keeps feathers on his walking-stick as well, one for every reason the marsupilami matters enough to be worth protecting.
In the series "My Friend Marsupilami", the current generation of Yamatunga (real name unknown) made several ocasional appearances, but it was his signature episode "The Protector of the Marsupilamis" that he almost failed his task to keep the marsupilami family safe from the dangers of the "Sky Stone", yet with Leo and his family, and the animal friends of the jungle, protecting the ailing creatures, Yamatunga found the ingredents needed for a complex-yet-effective antidote. As soon as all the marsus took their medicine, Yamatunga admits that he's at the point of his life when he should start looking for a successor, but the look on his face reveals he's already found his possible apprentice... Leo!