Caine is an alternate spelling of Cain, the first born of Adam and Even in the Christian mythos. Cain was a farmer, and his brother Abel was a shepherd. Both offered up sacrifices to God and God was not super accepting of Cain’s grains and fruits but he was well pleased with the smoking fat and meat and blood of Abel’s offerings. Cain, jealous, killed his brother Abel, committing the world’s first murder. God then banished Cain, sentencing him to a lifetime of wandering.
Then came the swarthy, dark-eyed countenance of Caine, dressed all in satin that was black and green, wearing a dark three-cornered hat set at a rakish angle, a green plume of feathers trailing down the back. He was standing in profile, one arm akimbo, and the toes of his boots curled upwards, and he wore an emerald-studded dagger at his belt. There was ambivalence in my heart.- 9 Princes in Amber Ch. 3
He wore satin that was green and black, and a dark three-cornered hat with a green plume of feathers trailing down behind. At his belt there was an emerald-studded dagger. He was dark.- 9 Princes in Amber Ch. 6