Marssi was a female Malon who lived in the 24th century. Marssi was married to Stvoran and had a daughter named Ella.

In the 2370s, Marssi was the controller of the tanker Apsac, a starship she had designed herself. In 2376, Marssi was forced to eject the antimatter waste from the tanker into an Iconian gateway after the Apsac was attacked by a Hirogen starship. Marssi and her crew were later killed by a Hirogen Alpha when he boarded the Apsac. (DS9 - Gateways novel: Demons of Air and Darkness)