Metalmena replaces Claire as the attendant aboard the computerized Galaxy Express 999 in the sequel narrative. She is a female cyborg with white eyes and no hair.

Integrated into the train's computerized control system, Metalmena initially opposes Tetsuro Hoshino's journey. She actively discourages his travels and attempts to block his reunion with Maetel, acting in accordance with the mechanized systems governing the 999.

As the story unfolds, Metalmena's role shifts significantly. She transitions from obstructing Tetsuro to actively supporting his quest. This culminates in her assistance as he confronts the mechanized empire and strives to reunite with Maetel, marking a departure from her initial programming.

Metalmena's character exists solely within the continuity of the sequel film. She does not appear in the original manga, subsequent OVAs, television specials, or other franchise spin-offs. Details regarding her origins before joining the 999 and her ultimate fate after the film's conclusion are not provided in the documented sources.