Ulduar

Rovas was a Romulan who served as the propulsion leader and the beta shift officer of the RIS. 

Overview
He made his first formal appearance in the series during the first season episode We're All In This Together, when he assumed command because the main three officers were busy repairing a faulty holodeck. Later in the series, he can be seen on the bridge when his superiors are out to repair other systems, or, sometimes, to repair engines himself.

Background
He is named after a titan complex of World of Warcraft, comprising several dungeons, including the eponymous instance.