Ozen "The Immovable" is a legendary White Whistle Delver who has made outstanding discoveries of the Abyss and retrieved numerous Artifacts of incredible value. Even among her fellow White Whistles, Ozen is renowned for her incredible physical strength. She is a mysterious person, shrouded by countless rumors that are absurd, but hard to refute. Ozen lives at the Seeker Camp within the 2nd layer of the Abyss, where she commands a small team of cave raiders known as the Subterranean Bandits. Ozen is a very tall and rather slim woman who stands over 2 meters in height. She has a strangely shaped monochrome hairstyle that conceals the scalp deformations caused by the intensive exposure to the Curse of the Abyss. Her eyes are pitch black and lusterless, giving her a rather unsettling and disturbing gaze. When fully equipped for delving, she wears bulky armor and a disc-shaped hat that covers her eyes. Her White Whistle is adorned with a pair of horns, giving it a bovine appearance. Despite being more than half a century old, she appears quite youthful, with only her white hair showing her age. A coldness dominates her personality, and she can often be cruel, cynical and apathetic. Even after discovering Reg's high durability during their fight, she continued to hit him anyways, citing that 'after a while [she] just got too into it'. She despises lying to children, and rarely lies to them — even if it means telling them brutal truths. Ozen has absolute control over her facial expressions, making her actual feelings (or lack thereof) normally ambiguous. However, she is not completely devoid of warmth and it is shown that secretly she dearly cares for Lyza. When Riko and Reg left the Seeker Camp to journey into the depths of the Abyss, Ozen revealed that she would have liked it if she didn't need to send them off before she could reminisce more about Lyza. She also treats her newest apprentice Marulk for the most part kindly, allowing him to stay at the Seeker Camp so that he wouldn't have to suffer under the surface's light.