Spare Parts originally lived in Kaleidoscope (Flux in his terminology) and was abducted by the Necromancer for experimentation. When the Necromancer discovered that Parts could be placed in a spirit jar and used to animate chimeric bodies he became a servant and incubator for temporarily unused body parts.
His voice functions much like a musical instrument and is capable of perfectly reproducing a wide range of chords. The Necromancer has made use of this capability to key many locks and other security features to specific chords so that Parts may act as a jailor and assistant. This utility is the only reason that Parts has been allowed to retain his own, original, voice, the only piece of him that’s original.
Introduced in #27 A Most Surprising Hero.