Lips is one of three identical triplets collectively known as the Mouth, alongside Teeth and Tongue. They operate as a unified entity, demonstrating near-perfect coordination in speech and combat, finishing each other's sentences and moving in synchrony like a single organism. This hive-mind dynamic enables exceptional teamwork that compensates for their individual limitations.

Recruited by a high-security prison warden, the Mouth was tasked with incapacitating former heavyweight boxer Iron Michael. During this mission, Lips and his brothers showcased proficiency in multiple martial arts, particularly boxing. They overwhelmed Iron Michael through coordinated attacks and strategic stomping techniques, exploiting their numerical advantage and seamless cooperation. Their effectiveness relied entirely on maintaining this group dynamic, as they acknowledged their individual capabilities were amateurish against formidable opponents.

The Mouth's critical weakness emerged when their unity shattered. Jun Guevaru intervened in the battle against Iron Michael and decisively defeated one triplet—implied to be Lips. The remaining brothers panicked, suffering a complete psychological collapse; the uninjured members fled in terror, with one urinating from fear. This incident revealed their absolute dependence on teamwork and inability to function individually under pressure.

Lips' documented involvement is confined to the prison arc, without appearances in other series seasons, films, OVAs, or spin-offs. Distinctions between the triplets are minimal, limited primarily to vocal differences in manga dialogue, and Lips possesses no unique physical characteristics or individual history.