The Black Onyx is a role-playing game developed by Bullet Proof Software. It was released, among other consoles and computers, for the SG-1000 in 1987. It was the last SG-1000 game to be released in card form, and the last to be published by Sega, but it is currently unknown as to whether it was the last SG-1000 game. MSX and PC-8801 versions had been released in 1983 and 1984, respectively, meaning this version is unusually late.
The game was followed by The Black Onyx II: Search For The Fire Crystal, which saw its original MSX release in 1984.