Rin Shiragiku is a member of the White Knights often seen with Kana Shiraishi. While they seem to be best of friends, she doesn't doubt to abandon Kana when Aika Sumeragi shot though Kana's shield, which was protecting them both. Like Kana she has Alien Tendrils in her body that she uses as weapons. Rin has a slim body and an average height at around 5' 4" with both green hair and eyes. Her most distinctive feature are her particularly huge boobs, especially taken into consideration her young age. She boasts the biggest breasts out of all the White Knights, with the possible exception of E.T.A.I. who is however much bigger in overall size. Near the end of Episode 3, Rin fights Aika together with Kana. After the later is defeated, she still tries to take her on by herself. They clash for some seconds, until a flying kick by Rin ends with Aika getting a hold of her legs and throwing her violently against a wall, which she hits head first. Her body then slumps down and falls to the floor, defeated. Though apparently left out of comission by the blow, Rin remains conscious after the impact and Aika graciously pardons her in exchange for information on the location of the missing girls.

Despite this act of mercy, Rin still attempts to launch a sneak attack on Aika as soon as the salvager turns her back on the seemingly surrendered high school student. While the victorious girl is calmly walking away, the White Knight makes it evident she is not all that affected from the fight, revealing a hidden blade made from alien tendrils and quickly going after Aika with the intention of stabbing her in the back. They are evil and supports female supremacy