There's Viktoriya. She has a unique relationship with Tanya. She's brave and her development throughout the story, especially in relation to Tanya, makes her an interesting character. Also, Erich von Rerugen. He represents the more traditional military thinking and his clashes and collaborations with Tanya are quite engaging.
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.
Sasuke could also be a great character to pair with Tanya. Sasuke has his own complex goals and a dark past, much like Tanya in some ways. They could form an uneasy alliance. Tanya might be intrigued by Sasuke's thirst for power and knowledge, and Sasuke could be interested in Tanya's unique abilities. Their relationship could be full of tension and mutual respect as they both pursue their own agendas in the Naruto world.
I'm not sure specifically as it's a fanfic. It might be a fan - created story within the 'Saga of Tanya the Evil' universe that has some unique elements perhaps related to 'lemon' which could imply some sort of zesty or different take on the original story.
A common theme is survival. Given the dangerous world Tanya is in, many fanfictions focus on how she continues to survive in various difficult situations. Another theme is power struggle, as she has to navigate through different power hierarchies.
Well, the 'Saga of Tanya the Evil Visual Novel' mainly focuses on Tanya's experiences. Tanya is a unique individual in a military - like setting. The story shows her strategic thinking, her interactions with other characters, and how she copes with the complex situations around her. It's a blend of action, strategy, and character - driven plot in a fantasy - war environment.