Yardio Voda Munagoul is a spirit bound by covenant to Eufinley Tsuge, serving alongside her at the Tsuge Divine Music Player Office. His combat prowess exceeds that of most four-winged spirits. Yardio maintains a relaxed and easygoing personality, a distinct counterpoint to Eufinley's serious and strict nature, shaping their ongoing partnership dynamic.

Their covenant began when Yardio impulsively attempted to seal it with a kiss, provoking Eufinley to punch him. Despite this rocky start, their partnership took hold. Yardio consistently displays open affection towards Eufinley, setting him apart from other spirits who might hide such attachments. He shares the contract with another spirit, Mashat, though Mashat is less frequently seen.

Yardio actively enjoys combat engagements, supporting the office's missions. His presence contributes significantly to the operational rhythm of the Tsuge Divine Music Player Office, where he works with other members, including protagonist Phoron Tatara and his contracted spirit, Corticarte Apa Lagranges.