Iria: Zeiram the Animation: Captured Twins

This is from the first episode of the OVAs. I don't know their names either.

Iria: Zeiram the Animation: Iria

The main protagonist and she was originated from the Batabitajira region of the planet, Myce, and is employed by the Ghomvak Security & Investigations, a bounty hunting agency. She can be stubborn and tomboyish at times and wanted to be like her brother who was an ace hunter. Her hunter ID number is 9799-5 which rank is identified by the color of a stone pendant which resembles a magatama and her pendant as an apprentice is pink with two small dots on it, but when she receives her full license and ID number she is given a blue stone with three red dots on it. This is from the third, fourth, and sixth OVAs.

OVA 3

OVA 4

OVA 6