Identified as LeCoultre and Piaget Serpentine, the Serpentine Twins are Topless pilots operating the combined Buster Machine Quarante-Deux. Distinctive facial markings visually mark them as twins.

Their primary goal involves attempting to awaken an entity they call "an eternal Topless," believing it could permanently eliminate space monsters and halt the fading of Topless abilities with age. This entity is later revealed to be an actual space monster. Lal'C Mellk Mal witnesses this creature violently attacking other Topless during the incident.

Their Buster Machine, designated Quarante-Deux (Buster Machine 42), possesses a unique construction allowing separation into two smaller units. Combined, it resembles a gargoyle-like head with design elements evocative of African masks. One unit forms the upper section featuring a rectangular head, long articulated arms, and spiked lower legs, while the other forms the lower jaw with a conical head, bulky legs, and spiked hands.

The twins' actions directly escalate the threats faced by the protagonists, leading to the emergence of the true space monster and subsequent conflicts involving Nono and Lal'C. Their storyline concludes within this incident.