Type OVA
A high school senior named Yotaro thought he was an only child—until he met his real mother and discovered that she has 19 daughters, from 0 to 18 years old. He ends up living with his "true family."
OVA
The Layzner OVA serves as an alternative version of the TV series. The first episode, titled "Eiji 1996", recaps the first part of the series (episodes 01-24). The second episode ("Le Caine 1999") takes place after a time skip, and contains episodes 26 through 37 (episode 25 of the TV series, being a recap itself, is skipped here). The final episode, "Seal 2000", is an expanded version of the final episode of the TV series (38) and features new animation and a longer epilogue.
OVA
The artificial sun that lights the frozen planet La Metalle is dying, threatening to extinguish what little life is left there. Queen La Andromeda Prometheum decides that the only way for her people to survive is for them to submit to Hardgear's transformation process, which will turn everyone's body into machines. The Queen's daughters, Emeraldas and Maetel, refuse to submit to this process, and fight to stay human.
OVA