|Debut (Light Novel)||Volume X|
|Debut (manga)||Eternal Song chapter 03|
|Appears In||Light Novels, Manga|
Nachtigall (小夜啼鳥 (ナハティガル) Sayonakidori (Nahatigaru) , Japanese and German for "Nightingale") is a birdcage-like Treasure Tool that once held the powerful Crimson Denizen known as Leanan-sidhe behind its bars.
Its function was to sing the Power of Unrestraint that was desired by the owner. This Treasure Tool played an instrumental role in Asiz's Grand Scheme. During the final battle between the Flame Haze and Töten Glocke, Leanan-sidhe was able to break free from her imprisonment, thus rendering Nachtigall useless.
|Offensive||Blutsauger • Bubble Loot • Chorde • Dance Party • Hystrix • Kiken no Kentō • Kisan no Taiken • Nietono no Shana • Regular Sharp • Traverso • Trigger Happy|
|Defensive||Azure • Bakuyagai • Orgel • Robe • Tarnkappe|
|Utility||Caina • Crystal Altar • Gehinnom • Giralda • Jettatura • Nine Eternal Divine Scales • Nomenclator • Obelisk • Reiji Maigo • Reshuffle • Saishuku no Shadan • Seireiden • Tendōkyū • Tessera|
|Miscellaneous||Atalante • Nachtigall • Trivia|
|Universal||Gordian Knot • Mekest • Shintetsu Nyoi • Tartaros • Trigon|