Vice-Captain Rosa upholds order and discipline as a senior officer aboard the Daiku-Maryu, directing daily crew operations and stepping into command during the captain’s absence. She leads critical missions and supervises juniors like Daiya and Puria through hazardous supply runs in contested zones. Her logistical expertise ensures efficient post-battle repairs, resource distribution, and sustained ship functionality. While navigating a desert city mission, she temporarily commands the vessel as the crew recovers from combat strain. A notable episode showcases her balancing morale and safety during a crew excursion to an amusement park, where she enforces security measures without compromising the team’s respite.