It's probably one of the worst matches in the world, really.
Dino is bright and happy and clumsy at the worst possible moments. Hibari is a stone cold man with a taste for blood and the most unsociable person alive.
Their earliest meetings ended with blood and bruises, despite Dino's best attempts at being friendly towards the younger boy. The Cavallone boss spent years trying to crack the cloud guardian's shell, to see if maybe there was some unseen softness left. If there ever was any softness, Dino sure as hell never found it.
It hurts Dino to know, whenever he gets a spare moment to think about it, that even though he is probably the one that Hibari trusts the most, he still knows so little about the other man.
But if years of being in the world of the mafia have taught him nothing else, they did teach him to be grateful for what he has. So even if he never gets to find out what goes on in the other man's head or what turned an innocent boy into such a delinquent, Dino will still cherish what he gets.
He'll cherish every quiet moment in between the punches and the kicks. He'll worship every inch of skin that he's allowed to touch. He'll cling to every bit of trust that Hibari is willing to give him. All because he loves this twisted, complex, beautiful man.