The Otome Heroine's Fight for Survival (Manga): Volume 3 by Harunohi Biyori

Alia accepts a job as a maid-in-training and guard to Princess Elena, one of the villainesses of the otome game. Under the tutelage of battle-specialist handmaiden Sera, Alia hones her combat skills even further. To her surprise, she develops a sense of kinship with Princess Elena—another gifted child bearing burdens far beyond her tender years—despite the two girls belonging to vastly different worlds. When Elena falls victim to a kidnapping plot, Alia rises to the occasion and runs to the rescue, realizing she now has something to fight for.