The Mechanisms

Jonny d’Ville, Captain First Mate: Vox, harmonica

Ashes O’Reilly, Quartermaster: Electric bass, vox

DrumBot Brian, Pilot: Percussion, accordion, banjo, guitar, vox

Gunpowder Tim, Gunner: Guitar, vox

Raphaella la Cognizi, Science Officer: Piano, vox

Marius von Raum, Medic: Fiddle, mandolin, vox

Ivy Alexandria, Archivist/Navigator: Flute, recorder, euphonium, trumpet

Aurora, Vessel

FORMERLY

Nastya Rasputina, Engineer: Viola, synthesiser

The Toy Soldier, ?: Vox, mandolin, glockenspiel, etc.

Other unconfirmed Mechanisms are listed here.