This was an idea I alwyas enjoyed: three giant ancient reptilian beasts each one ruling a particular place:

 Jeffron : Emperor of the Land, all land beasts thrive in his presence. He is often mistaken for mountain range. More of a guardian than an actual leader.

 MrCJB2 : Emperor of the Skies, all beasts who call the air their home fly freely under his wing. Has the most leader like qualities.

 Justathereptile : Emperor of the Oceans. Though he can protect the oceans and will do so fiercely, he is a bit of tyrant when he's starving.

All characters © to  Jeffron ,  MrCJB2 , and  Justathereptile