Made in Abyss

Made in Abyss (メイドインアビス, Meido in Abisu) is a manga series by Akihito Tsukushi. It has been serialized online via Takeshobo's digital publication Web Comic Gamma since October 2012, and has been collected in five tankōbon volumes. An anime television series adaptation by Kinema Citrus premiered on July 7, 2017.

Plot
The story is centered around an orphan girl named Rico who lives in the town of Ōsu on an island in the sea of Beoluska. The city surrounds a strange, giant hole going deep into the earth, which is commonly called the Abyss. The Abyss harbors artefeacts and remnants of a civilisation long gone, and is therefore the popular hunting spot for so-called Cave Raiders, who undertake arduous and dangerous descends into the mist-filled pit to recover whatever relics they can find. However, the deeper one goes into the Abyss, the more he is afflicted by a progressively fatal malady called the Curse of the Abyss; few who have descended into the lower regions have returned to tell of their experiences.

Riko's goal is to follow in her mother's footsteps and become a master Cave Raider (a White Whistle) and solve the mysteries of the Abyss. One day she explores the caves and discovers a robot who resembles a human boy.