Not much is known about Dan except for a few things. He was found frozen in a glacier, he has brute strength nearly on par to that of a T-Rex, he's the self-proclaimed King of the Dinosaurs on Isle Kyoryu, and he is the textbook example of brawn over brain. Due to his Neanderthalic origins (plus some suggested amnesia during the freeze), not only is his brain smaller than most of the other anthros, but he has an incredibly low IQ. He thinks he's a yeti (mainly due to him not knowing about his origins), he usually does the loser hand gesture, believing that it's a sign of bravery and heroism, and he always gets himself hurt through various ways. One noticeable thing about him is that he his saber toothed fangs, but they break off whether he gets hurt fighting a dinosaur or has a vine swinging accident (which explains the one missing fang in the picture). Surprisingly however, they're able to grow back in.
Dan's job is to live up to his own title and protect the prehistoric inhabitants of Isle Kyoryu from any danger, along with learning the ways of the spiritual guardians of the Elder Dragons by his mentor, Elden, the last living Elder Dragon.