Erebone (エレボーン) is the eponymous music for the skeleton boss in the MSX version of Dragon Slayer 4. The NES version of the game uses Taratunes's theme for all bosses. The song uses a lot of lower notes and has a sound of anxiousness, to be expected from a boss theme.
Both the MSX and MSX2 versions of Dragon Slayer IV use the same music. The song is track 16 in the KSS file and is played on the AY-3-8910 on the MSX and the identical-sounding YM2149 on the MSX2. The title is translated from Japanese on the official MSX soundtrack.