TV-Series
Description
Gascogne Rheingau serves as the head of the Registry system aboard the battleship Nirvana. Her primary responsibility is managing the ship's arsenal and supplying the Dread fighters with weapons for engagements against the Harvesters. She performs these duties both from within the ship and by piloting a delivery vessel in the field. As the leader of the Registry crew, she holds a significant position in the ship's hierarchy, acting as the third-in-command to Captain Magno Vivan, following Buzam A. Calessa.

In terms of personality, Gascogne is one of the most level-headed and composed members of the crew. During intense battles when her team might become overwhelmed by excitement or panic, she maintains her cool and helps them refocus with her characteristic reminder to "Smile, smile!". She is known for offering sarcastic advice when the situation calls for it, though this is not always appreciated by the recipients. Despite her sometimes sharp tongue, she functions as a big sister figure to many of the younger crew members, providing guidance and emotional support. A distinctive physical trait is the metal straw she constantly keeps in her mouth, which she can crush in her hand to bend it into the shape of a key. This object is a cherished keepsake from her sister. She has a particular dislike for being called by the shortened nickname "Gasco".

Gascogne's motivations stem from her dedication to the Nirvana and its crew. She takes her role as the ship's armorer seriously, equipping the fighters for survival against a powerful enemy. Her protective instincts are strong, often manifesting as a maternal or older-sibling concern for the younger members, especially the male protagonist Hibiki Tokai.

Her most significant relationships are with the crew she protects. She shares a particularly close bond with Hibiki, spending her free time with him and playing poker with him when the ship is not under attack. She serves as a mentor to him, teaching him to think more strategically and temper his brash nature. She also acts as a supportive figure to Barnette Orangello, another younger crew member who looks up to her. Within the ship's command structure, she works directly under Captain Magno and BC, serving as a reliable and effective leader who commands respect.

The character undergoes a notable development arc during the events of The Second Stage. When the Nirvana becomes trapped in a desperate battle against a Harvester mothership, Gascogne sacrifices herself to save Barnette. She rams her delivery ship into a Copy-Nirvana unit that is about to crush Barnette's Dread, successfully jarring her loose. However, this action draws the copy's attention, and it impales Gascogne's ship. The stricken vessel falls into the mothership and bursts into flames, apparently killing her. This event profoundly impacts the crew, who mourn her loss and struggle to find their "smile" again without her steadying presence. In a surprising turn, she later reappears during the final battle against Earth, piloting the same Harvester mothership she had crashed into, having apparently managed to survive and commandeer its systems.

Gascogne's notable abilities include her expertise in weapons management and supply logistics, ensuring the Dread fighters are properly equipped for combat. She is also a skilled pilot of her delivery vessel, capable of navigating dangerous battlefields to support her comrades. Her emotional strength and ability to remain calm under pressure are key assets, allowing her to lead her team effectively in crisis situations. She is also apparently skilled at card games, frequently playing poker with Hibiki.