Stormbringer is a computer game written by David Jones and released in 1987 by Mastertronic on the Mastertronic Added Dimension label. It was originally released on the ZX Spectrum, Commodore 64, Amstrad CPC and MSX. A version for the Atari ST was published in 1988. It is the fourth and final game in the Magic Knight series. The in-game music is by David Whittaker.
Magic Knight finally returns home, having obtained a second-hand time-machine from the Tyme Guardians at the end of Knight Tyme. However, there has been an accident whilst travelling back and there are now two Magic Knights - the other being "Off-White Knight", the dreaded Stormbringer (so called because of his storm cloud which he plans to use to destroy Magic Knight).
Magic Knight cannot kill Off-White Knight without destroying himself in the process. His only option is to find Off-White Knight and merge with him.
Source: Wikipedia, "Stormbringer (computer game)", available under the CC-BY-SA License.