Keiko serves as a supporting character in the "Nami SOS!" franchise, alternatively titled "Sexy Sailor Soldiers," specifically appearing in the 2003 original video animation "Nami SOS! First Battle." As a member of the Hunters, she targets and eliminates male sex demons. Her transformation occurs through the pendant "Eye of Lust," activating her battle form, and she employs a large, monstrous ray gun as her primary weapon. A veteran fighter with substantial combat expertise, Keiko contrasts with the less experienced recruit Nami, operating alongside fellow hunters Chisato, Naoko, and Tomoko.

Physically, Keiko displays maroon shoulder-length hair and brown eyes, presenting a teenage appearance. Merchandise and character databases identify her by the full name Keiko Mejiro (目白景子).

Within the OVA's narrative, Keiko engages in a pivotal confrontation against Mr. Sasao's demon clan. During a skyscraper skirmish, she intervenes to free Nami and Chisato from a demonic portal, reinforcing her position as a reliable combatant in the team.