A continuation of the epic adventure of plucky Riko and Reg who are joined by their new friend Nanachi. Together they descend into the Abyss' treacherous fifth layer, the Sea of Corpses, and encounter the mysterious Bondrewd, a legendary White Whistle whose shadow looms over Nanachi's troubled past. Bondrewd is ingratiatingly hospitable, but the brave adventurers know things are not always as they seem in the enigmatic Abyss.
| Actor | Role |
|---|---|
 Miyu TomitaRiko (voice) | Riko (voice) |
 Mariya IseReg (voice) | Reg (voice) |
 Shiori IzawaNanachi (voice) | Nanachi (voice) |
 Toshiyuki MorikawaBondrewd (voice) | Bondrewd (voice) |
 Inori MinasePrushka (voice) | Prushka (voice) |
 Sayaka OharaOzen (voice) | Ozen (voice) |
 Tetsu InadaHabolg (voice) | Habolg (voice) |
 Eri KitamuraMitty (voice) | Mitty (voice) |
 Natsuko HaraMeinya (voice) | Meinya (voice) |
 Shinji KawadaGueira (voice) | Gueira (voice) |
 Yoshimitsu ShimoyamaTankutsuka (voice) | Tankutsuka (voice) |
 Maaya SakamotoLyza / Narration (voice) | Lyza / Narration (voice) |
 Hiroki GotoUmbra Hands (voice) | Umbra Hands (voice) |
 Shinnosuke MusashiUmbra Hands (voice) | Umbra Hands (voice) |
 Akihiro TajimaUmbra Hands (voice) | Umbra Hands (voice) |
 Takayuki NakatsukasaUmbra Hands (voice) | Umbra Hands (voice) |
 Genta NakamuraUmbra Hands (voice) | Umbra Hands (voice) |
 Yuuki ShinUmbra Hands (voice) | Umbra Hands (voice) |
 Kosuke EchigoyaUmbra Hands (voice) | Umbra Hands (voice) |
 Aki ToyosakiMarulk (voice) | Marulk (voice) |
 Mutsumi TamuraNat (voice) | Nat (voice) |