Age: 350-something (relative to 35 in human years, but ageless-seeming to humans)
Species: I don't have a name for them but they're somewhere between Drule/Galra (Voltron) and Zentraedi (Macross/Robotech). They have pointed ears and skin and blood in cool colors. Kirin's skin and blood are blue. Skin can change hues slightly with exposure to light from different stars, and as Kirin spends more time near earth, his skin and blood take on a more greenish tinge from Earth's yellow sun. This is some kind of verdancification or something!
Body: Kirin has a slim frame but is well-muscled. Like Magus Chrono Trigger. He has this same frame in his true form as he does his human form.
Face: Kirin has a heart-shaped face that's mostly square. His nose is small, pointed and slightly upturned, with high cheekbones and a well-defined jaw that ends with a slight jut on the end of his chin. All features are apparent in his human and true forms. He looks almost exactly like his father.
Color Palette: As a human, Kirin has stark white hair with a cool blue undertone, and yellow eyes. His true form has the same white hair, but his eyes are solid yellow like DoU Lotor, with a "catlike" appearance to them.

Kirin is a hacker who works for his own ends. In the setting, an alien invasion force led by a kuudere general who likes to negotiate has encountered human civilization. He works for the current ruling family, who took power by force. This ruling family deposed Kirin's family and tried to "adopt" him, and love-bombed him into believing he still had a place in their society.

The ruling family's mother knew him before her husband murdered his father, and tried to tell him about all the bad things his birth family did to him (Kirin was physically abused by both parents). On paper, and in Kirin's young mind, this made sense, but as he grew older and saw his siblings by adoption ascend in the order, he became jealous because he still thought he'd get a turn.

When he realized that there was no getting his prospects, he got into a fight with his brother over the throne. He failed in his attempt to kill him and fled into space, disguised himself as a human, and integrated himself into the vast hacking scene. His adopted family has a huge reward for his return, issued by the brother that he tried to kill. They're using gaslighting and lovebombing to try to bring him back, but he's way, way beyond awake to their manipulations now.

The story widely known is that Kirin's parents were murdered, but they're actually alive and being tortured by the new rulers.