Rei Riku, Gin no Guardian Wiki

Its possible that she has some relation or connection to "The Collector", due the exact resemblance between the two of them and the fact they share the same voice actress; possibly even being the same person.

Anime by BLADE

Gin no Guardian 2nd Season in January – ANIMEFANDOM

Gin no Guardian – 01 – Random Curiosity

Suigin Riku, Wiki

Suigin Riku, Gin no Guardian Wiki

아이카 제로 : 네이버 블로그

Gin no Guardian, Isekai Wiki

Anime Spotlight - The Silver Guardian 2 - Anime News Network

A First Impression: Gin no Guardian Episode 1 – Moeronpan