Quick answer — Oldcodex performed 2 anime themes, including "Aching Horns" from High Speed! -Free! Starting Days-, "Feed A" from God Eater.
Oldcodex performed the anime theme songs "Aching Horns" (High Speed! -Free! Starting Days-), "Feed A" (God Eater).
Oldcodex's first listed anime theme is "Aching Horns", the ending of High Speed! -Free! Starting Days-.
