The wealthy family was in trouble, the brothers fled to a foreign country, and the sisters were separated on the spot.
They set up a trap in the casino, fight to the death in the suburbs, and cut off an arm with a single shot to preserve friendship.
The brothers broke up and went their separate ways. He became a tyrant from the bottom, and his brothers were as close as brothers.
After many years of encountering old friends and sisters by chance, after spending a lifetime of killing them, they finally gave in to their friendship, and the hero embarked on the path of retirement and reckoning.