Under Night In-Birth Wiki


Kuon (クオン)





The Eternal [Aion] (永劫(「アイオン」))
The Weaver of Eternity (永劫の紡ぎ手)


Night Blade

Battle Style


Twin katanas (In the past)
The Insulator (Temporarily)

Voice Acting

Japanese Voice:

Ayane Sakura[1]

Kuon (クオン) is an old member of the Night Blade and the main antagonist of UNDER NIGHT IN-BIRTH. Originally a noble young man, Kuon now hides in the shadows, manipulating those under him.


Kuon is Linne's older brother who has an immortal body of a Re-Birth. In the past, he was known as a genius swordsman and a man of chivalry, but at some point he started working towards his own unknown goals.


Kuon normally appears as a preteen boy, being just a head taller than his sister. His long, unkempt hair is brown in color with red streaks and his eyes are a deep red, though they are partially hidden by his hair

Kuon wears a large, hooded, white robe with a zipper going from the hood to the back and four undone belts; two around the hood and two near the waist. Underneath this robe, around eighty percent[2] of Kuon's body has turned into a Void as a part of the process of becoming a Re-Birth. His head, part of his chest and his left shoulder are the only parts of his body that still retain his humanity. The robe he wears is enchanted with a spell to make it easier for Kuon to control the Void within his body.[3] The large robe also covers most of his immortal body and helps to avoid causing unnecessary commotions.

In the past, Kuon wore a robe which left the left side of his body bare and his hair was much cleaner looking and tied into a ponytail. His eyes were also a more purple color like his younger sister, though the reason for the change in eye color is unknown.


Parts of Kuon's personality are only revealed by various characters in their arcade scenarios. It is mentioned how, in the past, he was a man of virtue and honor, having inspired Waldstein with his chivalry and being well-respected by many.

However, due to unknown circumstances, Kuon's personality appears to have taken a mysterious and possibly sinister turn, seemingly having severed ties to his former allies and manipulating Hilda into becoming his willing pawn and seemingly discarding her when she was of no further use. In the present day, Kuon comes off as cold and uncaring, mainly keeping to himself around others and preferring to keep his emotions out of conversation, giving him an eerie, sinister presence.

While Kuon is a natural combatant, he prefers to stay away from combat whenever possible and will not fight anyone unless he has a reason to, and even then, he will only resort to fighting as a last resort.


Episode: Nighttime Void (虚ろの夜語り)

Hundreds of years ago, Kuon was given incredible powers by the Hollow God and became what was nowadays called a Re-Birth. As a result Kuon gained an immortal body and eternal youth. Kuon served as the Night Blade's leader for many years. Kuon's chivalry was also the reason why Waldstein joined the Night Blade after Kuon saved him from almost turning into a Void.

After the Licht Kreis War, The Night Blade separated into two groups: The Reformists, and the Moderates, with Kuon leading the latter. A large battle broke out between the two factions with many lives lost. The village elder decided to split the knowledge of EXS into two bodies, Kuon himself, and his younger sister, Linne. Kuon became what was, essentially, a walking curse and would be kept alive for eternity from this. Burdended by this, Kuon left Linne in the care of Waldstein before leaving, with the other two following soon after.

However, for unknown reasons, Kuon seemingly vanished and has begun working towards an unknown goal. He manipulated Hilda into attempting to become a Re-Birth, but in Carmine's Arcade Path he steals the equipment back without Hilda's knowledge, presumably discarding her. Linne theorizes that he is after her "Seal of Soul Transmigration".

Episode: A Reluctant Hero (それでも俺は行くしかないだろ!?)

In the present day, Kuon travels to the city of Kanzakai; there, he meets Hyde in one of the city's parks. Knowing who he is due to his ties to his sister, Kuon instructs him to visit the large manor located within the park, stating that the meeting between him and the person who resides there is needed to make sure everything goes according to plan. Unnerved by Kuon's presence, Hyde questions his morality, but the Re-Birth simply brushes him off, stating that there is no reason for the two of them to fight. Acknowledging that Hyde will become an obstacle later down the line, Kuon vanishes, leaving the young man on his own.

Episode: Road to The Under Night...

Some time later, on the night before the Hollow Night, Kuon decides to visit the woman who resides in the park manor -- Hilda. Upon appearing before Hilda, Kuon tries to convince her to not go along with her plans of becoming a Re-Birth, stating what would happen if she were to fail. Kuon also states that Hilda is highly important to his plans and that her survival is key in the grand scheme of things. Despite Kuon's efforts, Hilda refuses to listen and tells him that she shall become a Re-Birth, no matter what. Kuon bids Hilda farewell, muttering under his breath that "Sistema Celeste" is soon close to coming to light before vanishing.


As one of the six Re-Births, Kuon is immortal with Hyde's Indulgence of Insulation currently being the only known weapon that can kill him. Hilda lists Kuon as one of the most powerful beings in the world, but no information about his abilities as a Re-Birth has been given thus far. He has been shown to vanish in a cloud of black and red fog, similar to that of a Void when it is killed. Kuon can do this as a means of teleportation, or to simply hide himself from others; however, his EXS can still still be sensed by other In-Births when it comes to the latter, as seen when he was acknowledged by both Hilda and Gordeau during their meeting. Kuon also has the ability to project himself via EXS.

While he isn't seen with them now, Kuon used to dual wield katanas in the past as seen in his duel with Waldstein. He also temporarily wielded the Insulator, which he used to cut off the EXS flowing into Waldstein's body, halting his transformation into a Void.

Kuon has been described as being a natural swordsman, being able to single-handedly defeat Waldstein in one-to-one combat.


Official Art
Normal (通常)
Happy (喜)
Angry 1 (怒 1)
Angry 2 (怒 2)
Comfort (楽)
Ed cha.png
Arcade Ending (Chaos)
Chronicle Mode Event (Nighttime Void 1)
Chronicle Mode Event (Nighttime Void 2)
Chronicle Mode Event (Nighttime Void 3)
Chronicle Mode Event (Nighttime Void 4)
Chronicle Mode Event (Nighttime Void 5)
Chronicle Mode Event (Nighttime Void 6)
Chronicle Mode Event (Nighttime Void 7)
Chronicle Mode Event (A Reluctant Hero)
Concept Art
Concept sprite from French Bread's Ustream
Concept art from Exe:Late[cl-r] gallery


  • Kuon's name comes from the Japanese word "kuon" (久遠), meaning eternity.
  • Kuon makes a cameo appearance in BlazBlue: Cross Tag Battle as an unlockable player card icon alongside Lex and Azel.


  1. Not mentioned within in-game Staff Roll. Revealed on French-Bread Broadcast on February 28th 2018.
  2. Void transformation percentage revealed on French-Bread Broadcast on February 28th 2018.
  3. Robe functions revealed on French-Bread Broadcast on February 28th 2018.


Playable Characters
Guest Characters
Non-Playable Characters