Linne (Princess of Reincarnation, or more commonly the Princess of Night Blade), is the main heroine of Under Night In-Birth and its updates. She returns in BlazBlue Cross Tag Battle as a playable character.
The princess of the Yato Clan and leader of the Night Blade, an organization which keeps order during the Hollow Night. Despite looking like a young girl, Linne has been alive for more than a hundred years; the Night Blade conducted experiments on her and her brother Kuon, allowing them to transfer their consciousness into a new body upon death and technically making them immortal. This caused a fracture within the organization which nearly reduced it to ruin, leading her to the new smaller modern-day incarnation. She is often being seen with the former Litch Kreis member now bodyguard Waldstein in most parts through her reincarnated life. She soon met a high school boy name Hyde Kido, who saved her from a common thug and mistaken Linne for a boy at first. When noticed the Voids are after Hyde who is late home from school, Linne saved him from the Voids as part of her debt to him, resulting his EXS Ability as an In-Birth awakened, which happens to be in possession of the Indulgence Weapon that is capable of ending her life and thus preventing her from continuing to possess more host bodies and ruining their lives, but not before training him to stop the Hollow Nights and discover Kuon's mysterious intentions.
Sometimes in the past while Linne was one of her previous reincarnation named Chitose, she and Waldstein met a younger Seth, a boy who grew up as an ninja-like assassin by one of his family assassin members who were part of the Nights Blade, and now a mercenary for hire who personally attempt to kill her before Kuon is next, as part of his atonement for Nights Blade’s sins.
- Linne has color palettes of the following characters: Dizzy (Guilty Gear), Jin Kisaragi, Chie Satonaka, Hyde Kido, Blake Belladonna, and Garnet (Steven Universe).