Geki is a tiny dragon(i'm so repetitive XD) who was found, literally found, by Greenchu(didn't see that coming). Greenchu adored the little guy and offered to make him his pet and Geki willingly accepted. There are 3 conditions to be Greenchu's pet.
1. Be undeniably cute
2. Greenchu gets to rub your belly anytime he wants, inside and out (since he can't be digested for some strange reason D;
3. He can feed you whatever and whenever he wants, to make you fat and huggable.
Geki, of course, had no problem with that since he just wanted some friends. He finds greenchu a little weird with all the hugging and feeding but he also finds Greenchu a valuble reliable friend.
Geki breathes fire, can fly with his tiny wings and can eat 3 times his normal body weight (which is 84.2 pounds). Dispite his angry appearance he's a very nice guy and only wants friends. He doesn't want food though since Greenchu feeds him enough as it is.