Can you recommend some similar light novels like 'testament of sister new devil light novel'?

Yes, it is. You can find it in many bookstores or online platforms.

Well, the complex character relationships are quite interesting. The main character's journey of adapting to his new situation with a devil sister is full of twists. For example, his interactions with his sister are filled with both humor and moments of deep connection.

Yes, it's worth reading. It has an interesting plot with unique characters. The story combines elements of fantasy, action, and some light - hearted humor, which makes it engaging.

The 'Testament of New Sister Devil' light novel is mainly about the story in a supernatural world. It involves various characters with unique powers and relationships. For example, there are often complex interactions between demons and other beings. It typically has elements of fantasy, adventure, and sometimes romance as the characters navigate their world full of challenges and secrets.

The Testament of Sister New Devil light novel is about a young man who suddenly finds himself in a rather unusual situation. He becomes involved with a devil sister, and from there, the story unfolds with a mix of action, humor, and the development of relationships. There are often battles against otherworldly foes, and the main character has to navigate through a world full of secrets and powers. The harem aspect comes in as he has interactions with multiple female characters, each with their own distinct personalities and roles in the story.

It's about a world where demons exist. Basara, the protagonist, finds his life turned upside down when Mio and Maria enter his life. Mio is a demon lord candidate, which means there are threats from other demons who don't want her to succeed. Basara has to protect her while also managing his feelings for her and Maria. The story is filled with battles, both physical and emotional. For example, Basara has to fight against other demons who are after Mio's life. And at the same time, he has to figure out his romantic feelings for the girls around him.

Well, one interesting aspect is its unique take on the harem genre. It combines elements of fantasy and comedy quite well. The characters are often full of charm, like the main character who has to deal with his new devilish sister situation in a rather humorous way.

Basara Toujou is one of the main characters. He has to deal with the sudden appearance of his new devil sister.

Sure. 'High School DxD' is a similar light novel. It also has elements of the supernatural and a male protagonist in a school setting with some romantic and action-packed storylines.

One of the main themes is the complex relationships. For example, the relationship between the main character and his sister is full of twists and turns. There's also the theme of power and how it is used and abused in the supernatural world depicted in the novel. Another theme could be about identity, as characters often have to figure out who they are in the midst of all the chaos and newfound powers.