Under Night In-Birth Wiki

The Night Blade's Secret Arts (夜刀の秘術(やとのひじゅつ)) are two powerful EXS abilities that can affect one's very soul. They are shrouded in mystery and are said to contain the knowledge of EXS itself.



Hundreds of years ago, the Night Blade tried to artificially create even more powerful EXS abilities. When the faction split into the Reformist and Moderate groups, the elder of the Night Blade's village chose to engrave two people with the very source of the Night Blade's knowledge of EXS into two different people in order to stop the conflict between the two opposing groups from escalating. The leader of the Night Blade, Kuon, volunteered himself and his younger sister, Linne, to bear the burden of this.

Hilda is quite interested in both abilities. However, Linne has stated that these abilities cannot be extracted from either her or her brother's bodies..


The Secret Art of Samsara, Reincarnation (輪廻の秘術(「リーンカーネイション」)) is the ability that's carved into Linne's soul.

It turns a person's soul into a parasite that transfers from one body to another once the host's current body dies. This makes it possible to live eternally in a certain sense. After the transference, the host body "remembers" the memories of the Princess of Night Blade. The host body's original personality will coexist with the personality of Linne's, causing a sort of rift between personalities and traits.

The Secret Art of Eternity (久遠の秘術) is the ability that's carved into Kuon's body. It stops a person's body from aging. By combining this ability and his status as a Re-Birth, Kuon is nigh-invincible and completely immortal.


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