Unaired short specials included in the second through fifth Blu-ray and DVD volumes Etotama.

It's a special project commemorating the 30th anniversary of Hokuto no Ken.

The age of the demons has begun. Dr Faust has foreseen this rise of evil. Unfortunately, he is near death and is unable to personally battle this upcoming threat. Faust entrusts a young boy, Shingo Yamada, to take the responsibility of ridding the Earth of this new evil presence. Faust finds a birthmark on Shingo's forehead that signifies that he is the chosen demon fighter. Faust summons from hell what may be humanity's only hope of surviving: a less than enthusiastic devil named Mephisto rises. After signing a pact in blood to save humankind, Shingo and Mephisto set out to battle the supernatural world. (Source: AniDB)

This is the OVA of The Galaxy Railways. The Galaxy Express 999 crashes on the off-limits planet of Herise and it's up to the SDF Sirius Platoon to assist.