They cut out his heart. Then they made him a god.
比干 was the king's uncle and the last honest man at a dishonest court. He kept telling 纣王 the truth. The king got tired of it, and decided he wanted to check something: it was said a true sage had seven openings in his heart. So he had it cut out to look.
What the king missed, everybody else saw immediately. A man with no heart cannot play favorites. He cannot be flattered. He cannot be bribed. He cannot love one petitioner more than another, because there is nothing left in him to do the loving with.
So he was not simply remembered. He was canonised, handed a post with duties attached: 文财神, the civil god of wealth. Not the armoured one on the tiger. The one in court robes, who governs money that is earned and paid rather than money that is won.
And the tradition is specific about what he is for. Merchants have prayed to him for centuries for 无偏无向,公平交易 — no bias, no leaning, fair dealing, nobody cheating anybody. That is not our reading of him. It is the reason he has the job.
He walked out of that hall alive, on a charm, and only fell later. He passed a woman selling 无心菜, the heartless vegetable, and could not help asking: a plant with no heart still lives, so what about a man? She told him a man without one dies. So he did. The heartlessness was never the problem. Asking the question was.
无心,故无私。 No heart, therefore no favorites.