Daimajuu Gekitou: Hagane no Oni
Japanese title: 大魔獣激闘　鋼の鬼
Alternative titles: Demon of Steel: Battle of the Great Demon Beasts, Steel Devil
Type: OVA
Source: Original
Episodes: 1
Status: Finished Airing
Aired: Dec 10, 1987
Duration: 56 min
Rating: PG-13 - Teens 13 or older
Studios: AIC
Genres: Horror, Sci-Fi
Themes: Mecha

In the year 1999, a team of UN scientists in an attempt to tap into a new energy resource on a deserted island called Sansara, unknownigly open a portal to another universe, unleashing dormant biomechanical entities. Three years later, Takuya Goroza returns to the island of Sansara urged by a mysterious request by college chum Haruka Alford. Little does he know, his old friend isn't what he appears to be... 

(Source: ANN)