Made in Abyss: Retsujitsu no Ougonkyou

After surviving Idofront, Riko finally possesses a White Whistle and descends with Reg and Nanachi into the Abyss's sixth layer, the Capital of the Unreturned. At this depth there is no safe route back, and every step leads into an environment stranger and more dangerous than anything they have faced before. Their exploration brings them to a village inhabited by Hollows, where value is governed by harsh rules that outsiders barely understand. As the trio becomes entangled in the village's mysteries and the traces of an expedition that reached the depths long before them, they uncover an old story of desire, sacrifice, and what the Abyss can turn people into.