I'm... relatively certain that he's an indrik but no one is entirely sure if there is more than one- he may well be a unique entity, that is endlessly reborn from the Earth when it dies. From the sparse information regarding them, no one has ever had the courage to try to study them and lived to tell the tale. But they say they are the King of Beasts, and he certainly seems to think so.

[ Which may sound like an exaggeration with that fat idiot peeking between slats, apparently unaware that if he can see them he can be seen. Rex points at his own eyes and then at Indrik, who flattens himself to the floor as best he can with his round belly- doesn't make him any more stealthy. ]

I came across him on a mountain, as an infant. [ He's choosing not to mention that happened after he nearly died killing Indrik's prior incarnation and watched this one appear. ] In hindsight, he may well have been fine on his own- but he seemed weak and needed help.