L'Sen was a Starfleet engineer in active service in the late 24th century. By 2381, L'Sen served aboard the USS Enterprise-E. During the Borg Invasion of 2381, the Enterprise engaged a Borg cube in the Azure Nebula. During the attack, Chief Engineer Geordi La Forge assigned L'Sen to ensure the structural integrity field was compensating for a hull breach. (ST - Destiny novel: Mere Mortals)