Talho Yuuki
Talho serves as the head pilot of the Gekko and is basically the glue holding the ship's crew together in a lot of ways. She's best friends with Hilda, and the two have a pretty solid dynamic that keeps things grounded on the ship.
Her main storyline revolves around her romantic relationship with Holland, which has some real depth to it—they've apparently been together since his military days, though the show doesn't spell everything out. Early on, she's visibly insecure about where she stands with him, especially when Eureka shows up and starts commanding his attention. She doesn't hide her jealousy well, which honestly makes her feel pretty real compared to a lot of anime characters who just smile through that kind of thing.
As the series progresses, her character develops beyond just being the worried girlfriend. She becomes more confident in her role on the Gekko and in her relationship, showing that both her and Holland's bond actually has legs to stand on.
Content compiled by AnimeList.moe from publicly available sources.