Ouzen

Ouzen, "The Immovable Lord," is a holder of the elite White Whistle rank who lives at the observation base, known as the Seeker Camp, on the second level of the Abyss. She commands a small team of cave raiders known as "The Layabouts." Ouzen was a mentor and a close friend of Riko's mother Lyza.

Ouzen is a peerless fighter—her unique relic "Thousand Pins" grants her superhuman strength, speed, and longevity. Even though Ouzen appears to be young, she attained the rank of a white whistle more than 50 years back. She is over two meters tall and has a peculiar hairstyle which conceals the scalp deformations caused by extended exposure to the Curse of the Abyss.

Ouzen has absolute control over her facial expressions, and her actual feelings (or lack thereof) cannot be guessed with any certainty. The reasons behind her actions are unknown as well—Ouzen rarely bothers to explain herself and, even when she does, it's impossible to know whether she's telling the truth or just toying with the audience.

(Source: Wikipedia, edited)