Yami no Matsuei, Byakko/Touda, opposites
You don't get more polar than a tiger and a serpent. Than a cat and a snake.
Byakko is a hedonist, he lives for pleasure and fun and all things exciting. He rolls in grass, chases butterflies and rubs on everyone. He purrs at the slightest attention, he pounces anything that moves, he's an exuberant bundle of affection unstoppable in anyway.
Touda watches it with the cool affect of the truly unimpressed. He sits motionless for hours in the sun, warily observing the world through senses dulled and crippled. He speaks when he must, he tolerates others when they refuse to leave him be, and he touches when he has no other choice.
Byakko is the playful warmth of an Eastern Wind, Touda is the restrained violence of a Black Star. Only in Tsuzuki do the two find any measure of similarity. Loyalty of differing flavors bind them to the same master with the same beloved chains. In Tsuzuki they find a degree of trust and strange companionship, a grudging sort of acceptance of each other as the lesser of many devils.
For even twined together, warm fur to chilled scales, they are opposites. Byakko likes to shout his desires; to thrust and grind and claw at broader strength, stronger muscle, until his tail bristles and he sinks his fangs into a meaty shoulder. Copper on his tongue and lightening in his veins. Touda is silent, eyes shuttered behind the glass of his visor, claws mindfully buried in the ground or bedsheets or his own thighs, venom aching behind his teeth as he's filled again and again with heat. Byakko's ecstasy is Touda's release.
There is nothing so vast as the gulf between a cat and a snake. There is nothing quite so puzzling and special as the bridge formed between them by the open arms of a man they both love.