There's Viktoriya Ivanovna Serebryakova. She is an important character who has a relationship with Tanya. She is more of a 'normal' person compared to Tanya in terms of her values and personality.
The main character is Tanya. She has to navigate the military world as a child with the mind of an adult. There are other characters like Visha, who is Tanya's close associate. And there are various military commanders and soldiers who are part of the military setting. They all contribute to the complex web of relationships and power dynamics in the Youjo Senki light novel.
The main themes include the transformation of the protagonist. She goes from an ordinary person in one world to a key figure in a war - torn world in the light novel. Additionally, there's the theme of loyalty. Characters have to decide who to be loyal to, whether it's their country, their comrades, or their own beliefs.
It's a military-themed light novel. It follows the story of a salaryman who is reincarnated as a young girl in a world of magic and warfare. The protagonist uses her knowledge from her previous life to navigate the military and political situations in this new world.
Youjo Senki started as a light novel. The manga was based on the concepts and characters established in the original light novel. Usually, light novels offer more in-depth world-building and character development, which can then be adapted and visually presented in the form of a manga.
Tanya Degurechaff is the most important character. She is a reincarnated salaryman in a girl's body in a military - focused world. She is highly intelligent and ambitious in the military.
The theme of identity is present as well. Tanya, with her reincarnation into this new world, has to deal with her new identity and how it affects her place in society and the military.