Came up with him from a fan fiction Called the chase, Callos was not born a pony either. He is what is know as a mirror traveler though is able to use magic portals to cross into other whens and wheres. He comes from one of many worlds that are nearly identical say in history but one world maybe full of ponies where the others are human like or even anthromorpihc types ( ponies wit human like forms.) Callos was born in a world that had humans, elves, and harpies as the three races. Humans being like the earth ponies, elvish people (unicorn), and harpies ( Pegasus). Long story short after his father sombra turned evil after losing his mind over the death of his wife. Sombra tried to kill Callos but not being able to flung into a portal to a random universe but was pulled in along with. Once Callos had woken up he went after his father to keep him from harming anyone else.