Marulk

マルルク

Maruruk is a Delver residing in the "Seeker Camp" on the 2nd layer of The Abyss, alongside the legendary White Whistle, Ouzen the Immovable. Despite his youth, he holds the rank of Blue Whistle because he is the direct apprentice of a White Whistle.
When he was very young, he fell in an accident and nearly died before Ouzen rescued him. After this event, he decided to remain in the Abyss and become Ouzen's disciple. However, his eyes later developed an extreme sensitivity to light, so he never returned to the surface. He manages the camp's telescope and frequently keeps watch on the surroundings to spot arriving Delvers, allowing a gondola to be lowered in advance.
Maruruk is a young boy with short blue hair and a round face. His feminine features and maid outfit cause people to mistake him for a girl, but he is actually male. Although the details are unclear, it seems Ouzen forced him to dress as a maid.