Echo Rec is a young male scrap gatherer with black hair and black eyes, laboring under Mayor McGee's supervision within the post-apocalyptic settlement of Liverchester. He excavates the town's garbage mountains, haunted by childhood tales of the Merle-Wald forest where local folklore warns humans transform into terrifying Earless entities, fears adults found amusing. Echo harbors a deep fascination with Players—heroes battling the Earless using mechanized Equipment—ignited a decade prior by witnessing the historic "Project Freedom Festival" battle involving the legendary Jimi Stonefree. Despite aspiring to join them, initial timidity and limited social awareness, often causing confusion through misinterpreted interactions like sharing memorabilia, resign him to Liverchester's mundane existence.

His life shifts dramatically upon discovering an amnesiac girl with an input jack buried in scrap, whom he names Mu. After nearly falling to his death retrieving Equipment for her, Echo resolves to abandon passivity and accompany Mu on her journey, driven by the realization he would regret dying without pursuing dreams beyond Liverchester. Initially anxious and timid, struggling with fear during travel and confrontations, he serves as Mu's technical support, maintaining her Equipment while they seek her origins and Jimi Stonefree. His fanboy enthusiasm persists, manifesting in actions like seeking autographs from notable figures such as the antagonistic Neubaten Sisters.

Gradually developing resilience and determination, Echo's commitment is tested when Mu is brainwashed into antagonistic actions. Confronting his fears to support her, he plays a pivotal role in mediating peace between humans and the Earless, revealed as sentient "Listeners." His unwavering belief in Mu enables her rejection of conflict, solidifying his transition from hesitant dreamer to an active participant shaping their world.