@STRESSED BY A MOUNTAIN OF BOOKS
If you mean the woman that swore revenge against Liam, it's the rival of the mecha merchant glasses girl.
She got too stressed by Liam choosing the dork's expensive tech and chose to train so she can be hired into the Liam's crew so she can get her revenge easier. As for what her plans are and how successful she will be, well we all know how "lucky" the guide is.