Under Night In-Birth

The first entry in the series, Under Night In-Birth, was released exclusively as an arcade game using Sega's RingEdge 2 arcade board on September 20, 2012 by Sega in Japan. In March 2013, support for Sega's ALL.Net P-Ras Multi service was added.^[11] A major revision, subsequently entitled Under Night In-Birth Exe:Late (アンダーナイトインヴァースエクセレイト, Andā naito invāsu ekusereito), was released on September 9, 2013. This updated version of the game would receive a port published by Arc System Works for PlayStation 3 in Japan on July 24, 2014.^[12] A 2015 release for North America and Europe was later announced,^[13] with the North American version published by Aksys Games on February 24, 2015 and the European version released by NIS America on February 27, 2015. Exe:Late was released on Steam for Microsoft Windows systems on July 12, 2016.

A further update to the game entitled Under Night In-Birth Exe:Late[st]^[14] was announced on May 15, 2015.^[15] Under Night In-Birth Exe:Late[st] was released on PlayStation 3, PlayStation 4, and PlayStation Vita in Japan on July 20, 2017,^[16] and in North America and Europe on February 9, 2018.^[7] Arc System Works later published this version on Steam for Microsoft Windows systems on August 20, 2018.^[17]

A final revision of the game, entitled Under Night In-Birth Exe:Late[cl-r]^[18], was announced on August 3, 2019 at Evolution Championship Series. It was released for the PlayStation 4 and Nintendo Switch on February 20, 2020 in Japan and North America and February 21, 2020 in Europe.^[19] A version for Steam for Microsoft Windows was released on March 27, 2020, superseding the Exe:Late[st] release from 2018.^[20] The PlayStation 4 and Steam versions of Exe:Late[st] received updates to match the contents of this revision, while those who purchased the PlayStation 3 version were eligible to upgrade to the latest version via a limited-time discount, which ran until April 30, 2020 in Japan and North America, and April 31, 2020 in Europe. New content exclusive to Exe:Late[cl-r], such as a new playable character and additional character palettes, could be added to Exe:Late[st] through the purchase of paid downloadable content.^[21] The game was released for Amazon Luna on January 21, 2021.^[22] An arcade port of Exe:Late[cl-r] using Sega's ALL.Net P-Ras Multi service was released on April 15, 2021.^[23]

On September 21, 2021, director Nobuya Narita and composer Raito confirmed on Twitter that the "next" installment of Under Night In-Birth was in development. Narita expressed interest in the announcement of said title coinciding with the tenth anniversary of the original release of the game. It was not explicitly stated whether this referred to a new version of Under Night In-Birth or a wholly new title set within the same universe.^[24][25] Eventually during Evolution Championship Series on August 4, 2023, the title was announced to be a sequel titled Under Night In-Birth II [Sys:Celes] and it was released on January 25, 2024. It serves as a final chapter of the Hollow Night storyline.^[26] It features DLC characters in season passes.^[27]

During Paris Games Week 2023, an open beta test for [Sys:Celes] was announced to take place from November 17 to 20, 2023 for PlayStation 4 and PlayStation 5.^[28] An early access release was made available for PlayStation owners in Japan, Hong Kong, England and the United States on January 21, 2024.

After Stormy Night tournament on November 2, 2024, an arcade version for Sega's ALLS was announced. It is be powered by ALL.Net P-ras Multi version 3 and was released on March 27, 2025, in addition to the first two DLC characters will be available at launch, while the remaining DLC characters will be added post-launch at a same day as their DLC console releases.^[29] A new DLC fighter, Izumi, was announced at EVO 2025.^[30]

Under Night In-Birth is a 2D fighting game with similar mechanics to Melty Blood, Guilty Gear, and BlazBlue. Characters have weak, medium, and strong attack buttons, along with a fourth one tied to the game's Grind system. Attacks can cancel into each other in any order, and they can cancel into special and super attacks.

The Grind system, abbreviated to GRD in the game, is a tug-of-war mechanic between players that rewards them for certain defensive or offensive actions. This is visually represented by an on-screen gauge called the Grind Grid, which shows the influence each player has during a match. Playing aggressively and utilizing system mechanics well increases a player's influence over the Grind Grid, while actions such as taking damage and retreating lowers their influence. At set intervals of time, the game evaluates which player has the most influence over the Grind Grid and rewards the player with various advantages, such as a temporary damage increase and the ability to cancel any attack at the cost of resources. When utilized poorly, such as failing to guard against an attack with the appropriate defensive shield, a player can temporarily be locked out of functions related to the Grind system and placed at a disadvantage.

A traditional super meter known as the EXS Gauge fills up whenever players attack or get hit. Characters can expend resources from the gauge for various functions, such as enhancing special attacks, performing super attacks known as Infinite Worths, or changing momentum from a defensive position. At low health, characters can also use a unique super attack called an Infinite Worth EXS, which are highly damaging and often feature a cinematic element when performed successfully.

Each later release after the original adds new features:

• Exe:Late adds Guard Thrust, a defensive option, and Force Functions, a unique character specific action that costs GRD to use.
• Exe:Late[st/cl-r] adds Cross-Cast Veil Off, a combo-based burst where characters with at least half a bar of super meter and Vorpal state can cancel combos into a Veil Off burst; and a prequel-based visual novel series Chronicle Mode.
• II [Sys:Celes] adds not only custom coloring and rollback netcode which first appeared in Melty Blood: Type Lumina, but also a Celestial variant of GRD Vorpal when players' GRD is at level six or beyond, and a dodge roll-based Creeping Edge. Additionally, it also includes an exclusive special attack function that can only be cancelled from normal attacks, either as fourth option of improved Smart Steer or A+B, akin to the first two options of Rapid Beat, and Moon Skill from Type Lumina.

Every month, since feudal times, a phenomenon called the Hollow Night brings forth invisible creatures called Voids. They feed upon a power known as EXS, a latent resource within every human, and they harvest EXS from those who are unfortunate to wander into the Hollow Night. Many of these attacks end in death, insanity, or a human being transformed into a Void and the city of Kanzakai has been facing an ever increasing amount of cases of missing people due to these frequent attacks. Those who survive these encounters become beings known as In-Births, gaining the ability to manipulate their bodies' natural EXS. After surviving a Void attack, high school student Hyde Kido develops his own power after narrowly escaping with his life thanks to the assistance of his impromptu savior, a mysterious girl named Linne. She explains that on-top of being an In-Birth, she has been alive for the past 500 years and has been seeking a way to end her life permanently, with Kanzakai being her most recent stop on her journey. She explains that Hyde's newly developed ability holds promise in being the one to finally end her cursed existence and she has him make a promise to end her life when the time is right. Before that however, Linne has her sights set on stopping a group of In-Births in town known as Amnesia, led by a woman called Paradox, from ascending to become a Re-Birth, a powerful existence that surpasses ordinary In-Births.

Other groups of In-Births out in the Hollow Night prepare to make their way to Paradox's Altar for their own reasons. The Licht Kreis, a foreign group of In-births intent on policing the usage of EXS around the world has returned to Japan to investigate the city's growing case of Voids and In-Births while the ancient group of In-Births known as the Night Blade continue to patrol their ancestral homeland.

By the end of the Exe:Late sub-series, Hyde and Linne confront Amnesia's leader, Hilda the Paradox and bring an end to her plans. However, the true mastermind behind Hilda's movements, among many others, Linne's older brother, and the original wielder of Hyde's sword, Kuon the Aeon has yet to show himself during the Hollow Night. He would reveal himself a month after Hilda and Hyde are defeated. For months, Hilda temporarily becomes a Zero Vessel and loses her power, before she regains it back. When Kuon makes his true plans that will lead to the destruction of the world, Linne goes on a journey to confront him alone.^[26]

The original release of the game included ten playable characters, with two more being added post-launch before the game was retitled to Exe:Late. The roster currently has a total of 27 fighters as of Under Night In-Birth II [Sys:Celes] and one of its Season Pass DLC, with two guest characters from other fighting games. Most of these characters who are added after the original title originally either non-playable or being referred by most of them in previous entries. The game has Japanese-language voice acting.^[31] Some characters who first appeared in Exe:Late to Exe:Late[st] later appeared in BlazBlue: Cross Tag Battle, where they received English voice actors for the first time.^[32]

Introduced in the Exe:Late sub-series

• Hyde Kido (城戸 灰都(キド ハイド), Kido Haido): A second-year high school boy. He is attacked by a Void on his way home from school but is saved by Linne. Feeling indebted to her, he joins her cause in stopping Hilda's plans, and eventually cede to her wish and end her immortal life. He gains the ability to wield the legendary blade called the Insulator that holds the power to kill immortals.
• Linne (リンネ, Rinne): An ancient immortal princess of the Night Blade. She has roamed the country for the past 500 years. She was cursed as an immortal alongside her older brother, where Linne's soul transfers to a new host body against her will every time she dies and her current body is a child who goes to elementary school. Her friend is Chiharu (チハル).
• Waldstein (ワレンシュタイン, Warenshutain): A giant and brutish half-Void who fights with weaponized armed claws. He has some wisdom gained from his centuries-long life. He is a former member of the anti-Void organization Licht Kreis, before his defection to Night Blade after a war between two organizations, particularly after Kuon saved him from becoming a Void-Fallen. Honoring his oath to Kuon, Waldstein served as Linne's bodyguard for over 500 years, and thus the reason he cannot keep his promise to his former leader and lover, Adelheid until the time comes during last night, where he leaves Linne and sides with Kuon at Sys:Celes. Despite the recent changes on Licht Kreis caused by Waldstein, Adelheid still forgives him.
• Carmine Prime (カーマイン・プライム, Kāmain Puraimu): A delinquent and selfish third-year high school student. His prowess has gained the attention of many in-birth organizations across the city, but his severe aversion to groups has him antagonize nearly everyone he meets. He uses a strange red substance in battle disguised as blood, and thus suffers from placebo wherein he feels weakened should he use his powers for too long. He aims to defeat Kuon and becoming a powerful Re-Birth.
• Orie Ballardiae (オリエ・バラーディア, Orie Barādia): A second-year high school girl and a Rank 5 Executor of the Licht Kreis. She was orphaned ten years prior to the story where her parents were killed by a Void who had the ability to speak. She joined the Licht Kreis and trained as one of their warriors. She is sent to Kanzaki alongside her friend Lex Bartholomew, to go undercover, observe and report on the worsening In-birth situation in Kanzakai as a student "Orie Harada" ("原田 織依"(ハラダ オリエ), "Harada Orie"). She becomes close friends with Hyde.
• Gordeau the Harvester (ハーヴスター・ゴルドー, Hābesutā Gorudō; Harvester Gordeau): A mercenary, a bartender, and one of the co-founders of Amnesia, an organization seeking to dominate the Hollow Night. He leaves the organization after an accident involving the death of a friend and fellow Amnesia founder, Roger the Survivor (サーヴイヴー・ロジャー, Sābaibā Rojā; Survivor Roger), who was transformed into a Void-Fallen during the same night as Amnesia's war against Bankikai.
• Merkava (メルカヴァ, Merukava): A mysterious humanoid-Void capable of speech. He is amnesiac, before he was transformed into a monster. He was once a human allegedly seeking to become a Re-Birth, but the process failed and he was left with a human conscious living inside a Void's body, constantly driven to sate an unnatural hunger, such as his unwittingly murder on Orie's parents. As a Void, Merkava does not use EXS, but a power known as False (abbreviated as "FLS"). He is the only character to have two Arcade endings in Sys:Celes, with using Infinite Worth EXS against Kuon in the final stage of Arcade Mode results a bad ending. It is revealed in Merkava's good ending that a transformation into a Void and Re-Birth leaves a normal human naked for the entire time.
• Vatista (バティスタ, Batisuta): Unit code, 10,067. An ancient "Autonomic Nerve" designed as an anti-Void weapon from eons past. Due to her inhuman origin, she lacks common sense and understanding of human society and social norms. In ages past, she gave her seventh wing to Kuon that eventually became the Insulator. Vatista awakens from her slumber after 500 years due to the massive fluctuations of EXS in the city, and she seeks to find the one responsible. Like Merkava, Vatista uses the power of FLS rather than EXS and she is not a human being.
• Seth the Assassin (アサシン・セト, Asashin Seto; Assassin Seth): A first-year high school student and a descendant of the original Night Blade clansmen. He met Linne ten years ago, when she was inhabiting another body named Chitose (チトセ). Seth made a promise to her that he would free her from her unwanted immortality but his powers were incompatible with his goals. In the present day, he gains a pair of daggers named the Eliminators from Chaos, who himself was supplied by an unknown benefactor, in exchange for his skills to be used for Amnesia's purposes in targeting problematic In-births in the city. He holds some animosity towards Hyde as the one assisting Linne, until Hyde's encounter with Kuon at the end of Exe:Late makes him realize what he and Seth must done to Kuon and Linne.
• Yuzuriha (ユズリハ): A carefree swordswoman hailed from the clan who abandoned the Night Blade centuries ago and founded the Dual Moon Single-Blade Style of swordsmanship. Wielding her family heirloom the Iris Blade: Kamiji-no-Homare, which she nicknamed "Ayame" (アヤメ), Yuzuriha acts as the neighborhood guardian, patrolling the night to subdue quarrelling in-births and save people from Void attacks. She is a close friend of Hyde, before an awkward incident led to them avoiding each other and Hyde being an In-Birth.
• Hilda the Paradox (パラドックス・ヒルダ, Paradokkusu Hiruda; Paradox Hilda): The first boss character of the Exe:Late sub-series, and the leader and co-founder of Amnesia. She seeks to become a Re-Birth. Her excessive use of her powers have caused her "other-self" to take over her psyche, slowly turning her more unhinged and bloodthirsty to the point it has evolved her powers.
• Bloody Chaos (ブラッディ・ケイアス, Buraddi Keiasu): Real name Kei Asuma (明日真 景(アスマ ケイ), Asuma Kei). Amnesia's chief tactician and de-facto second-in-command who has the ability to project and manifest a creature based on the catalyst of his choosing that is limited to books. He accompanies Azhi Dahaka (アジ・ダハーカ, Azi Dahāka), a monstrous lizard-like Void summoned from the Chaos Code stolen from a Licht Kreis facility shortly before joining Amnesia. He is the one who hired Seth with the Eliminators he gained from an interested third party.
• Nanase (ナナセ): A second-year middle school girl who is attacked by a Void and turned into an In-Birth. Misunderstanding how one becomes an In-Birth, she mistakenly believes Hyde to be responsible for her transformation despite him being the one who saved her. In Sys:Celes, Nanase seeks Tsurugi at EFG, due to his past histories with Hyde, and her friend Phonon (Yoshiko).
• Byakuya (ビャクヤ): A middle school boy accompanying his "sister", Tsukuyomi (ツクヨミ). In truth, the real one died in a car accident, and Byakuya lost his sanity and will to live. In an attempt to die out in the wilderness, Byakuya becomes an In-Birth when he encounters a powerful Void. Byakuya eventually meets Strix (ストリックス, Sutorikkusu), a former member of the defunct Bankikai, who he insists on escorting around the Hollow Night because she resembles his sister. Strix accepts her role, because she cannot access her powers to defend herself and enhance those who aids her, as a result of becoming a Zero Vessel (器割れ(ゼロヴェセル), Zero Vesseru). He helps Strix search for her former fellow member, Zohar (ゾハル, Zoharu), who went insane after the presumed death of their leader, Ogre.
• Phonon the Chermeti (シュメティ・フォノン, Shumeti Fonon; Chermeti Phonon): Real name Yoshiko (良子(ヨシコ)). Nanase's friend with a chūnibyō personality. A former member of a student-led organization called the Exist Force Guardians (EFG), who seek to protect their fellow students from Voids and groups of other In-Births. She joined the organization, but she promptly leaves to use her powers freely.
• Mika Returna (ミカ・リターナ, Mika Ritāna): A tenth rank Executor of Licht Kreis and a member of Orie's team. She is reckless, stubborn and hyperactive to the point she is often punished by those above her by rank for her hastiness. Despite her petite frame, she wields extraordinary strength and her gauntlets amplify them even further. After a series of tribulations escaping from Licht Kreis' headquarters in Europe, Mika arrives in Japan to join her friends.
• Gaien Enkidou (円鬼堂 凱庵(エンキドゥ ガイエン), Enkidō Gaien): An experienced martial artist who goes by Enkidu (エンキドゥ). He felt that human opponents did not challenge him enough for his quest for strength and became an In-Birth to challenge those with supernatural abilities. He ends up joining Amnesia after Hilda promises him that in their organization's quest for dominance she will provide him all the worthwhile challengers he seeks. He particularly wishes to duel Gordeau and Waldstein. However in Sys:Celes, he defects from Amnesia, and sides with Kuon and Waldstein. The shackle on his wrist meant to suppress an evil within his EXS from becoming a fighting hungry Void-Fallen, should Enkidu unleash its full potential and breaking his oath when necessary at the same time.
• Miyashiro Erika Wagner (宮代(ミヤシロ)・エリカ・ワーグナー, Miyashiro Erika Wāgunā): A high-ranking fourth Executor of Licht Kreis. Famed as the prodigious "Void Hunter", she is Orie's self-proclaimed rival and was sent to school in Japan to not only grow past her sheltered upbringing, but to be punished for her brutal methods on the job. She was responsible for mercy-killing Roger when he transformed into a Void during the duel between Ogre and Hilda. Wagner attended the same school as Hyde, Orie, Seth, and Carmine, as shown in her interactions with Hyde in Sys:Celes.
• Londrekia Light (ロンドレキア・ライト, Rondorekia Raito): Wagner's self-proclaimed rival and a member of Ritter Schild, a male-only branch organization of Licht Kreis resulting from Waldstein's defection to the Night Blade that made Licht Kreis' supreme leader Adelheid discharged the men from her organization, initially believe to have kicked them out for no reasons, until it is revealed in Sys:Celes to be relating to Waldstein's reasons behind his current conditions and situations since almost transformed into a Void Fallen. He seeks to have both organizations make amends and rejoin as one to strengthen their ability to help others. He also offers Merkava a chance to become human again should the Ritter Schild find a way to reverse his condition.

Introduced in II [Sys:Celes]

• Kuon the Aeon (永劫のクオン, Eigō no Kuon) The second boss character of the series and Linne's older brother. Before becoming a Re-Birth, he was once a noble leader of the Night Blade and the original wielder of the Insulator before Hyde. After many centuries of harboring the Seal of Immortality, he progressively became more corrupted and his transformation into a Re-Birth changed his physiology, where half of his human body transformed into that of a Void, akin to the transformation. He currently fights with eight flying blades resembling the Insulator. He was also responsible for giving Seth the Eliminators through Chaos. His goal is to amass EXS to tear through the Hollow Night, access the world of Voids, and hunt down a particular individual who was responsible for the Insulator's disappearance after the Litch Kreis War, Higan (ヒガン), resulting a world merge between human and void worlds.
• Kaguya Jingu (カグヤ・ジングウ, Kaguya Jingū): A sixth rank Executor for Orie’s team. Unlike her friends who come from orphaned backgrounds, Kaguya hails from a renowned family with ties to the Licht Kreis. However, back in her youth after losing her parents, she became an orphan street urchin who struggled to survive with her family's dual guns, until a Litch Kreis high ranker, Silvaria raised her. She was originally assigned a different mission from Orie and Lex, but she returns to Kanzakai to confront Kuon.
• Tsurugi (ツルギ): The second in-command of the EFG who wields a human-sized shield, and a close friend of Hyde. He is responsible for bringing in new members for the organization and is considered the group's most capable fighter. When Kuon plans to conquer the world during a final night, Tsurugi sets out to save everyone.
• Uzuki the Black Monger (ブラックモンガー•ウズキ, Burakkumongā Uzuki; Black Monger Uzuki): A disturbing pink-haired necromancer. She accompanies her minions, J.J. and Tempest. A former member of Amnesia in Exe:Late sub-series, she left the organization in Sys:Celes, due to an odd between her and Hilda. As confirmed by Vatista and Byakuya, Uzuki's EXS is actually a FLS, which is very common to Voids and Autonomous Units. Due to her nature as a FLS user who retained her human appearances and outfits instead of transformed into a Void, Uzuki might be suspected to have secretly become a Re-Birth earlier.
• Ogre (オーガ, Ōga): A leader of a defunct rival organization, Bankikai, with an ability to summon a power of from the gate of a titular devil king, a god of death Hades, such as energy attacks and a transformation into a horned Void-like form. He was thought to have died after saving Gordeau from a Void-Fallen Roger. In reality, Ogre survives and was pulled the Abyss that corrupted Roger. He escapes safely from it as of Sys:Celes to find out what happened recently since his disappearance back in Exe:Late sub-series.
• Izumi Shirogane (白銀 泉(シロガネ イズミ)): A mysterious white haired young girl and an acquaintance of EFG. She earned the moniker "Serene". She is guided by an Initiator nicknamed Elefee (エレフェ, Erefe), the third known Indulgence Weapon besides Insulator and Eliminator, which serves as a final key to unlock the door of the final night. Elefee's current form is a tamed sentient Void-like flying fish who can change shape into a scarf form. Izumi wishes to be free from Elefee when the time comes.

Guest Characters:

• Sion Eltnum Altasia (シオン＝エルトナム＝アトラシア) from the fighting game series for Tsukihime franchise, Melty Blood. She is referred to as Eltnum (エルトナム) within the game's context. One of the main characters in Melty Blood, Sion has a supporting role in the main story of Under Night In-Birth. She often remarks on other fighters as if they are novices and shows awareness that she is a character from French-Bread's past games, with Sys:Celes has her sought to find a luminous place for her full debut in Tsukihime remake timeline, after the era of A piece of blue glass moon. This awareness extends to meta-references about appearing in arcade games and information related to that subject, such as the Sega Naomi hardware used for Melty Blood Actress Again and Team Arcana's defunct parent company, Examu.
• Akatsuki (アカツキ) from Subtle Style’s fighting game series Akatsuki Shisei Ichigō/Blitzkampf, and its sequel EN-Eins Perfektewelt, who served as the titular protagonist of the former game. He has no role to the main story, but little known about his displaced involvement this series' storyline takes place during his titular game's canon storyline between his venture at China, and prior to his encounter with Kanae and Fritz, during his return to Japan. However, in contrast to his actual displaced storyline in this series, his win quote in Sys:Celes mistakenly took place between his game and EN-Eins. Initially, during Exe:Late sub-series, unlike Sion, Akatsuki is in no way self aware and only looking for a way to return to his duties. Though he ultimately becomes aware of his displaced involvement in the main story of the game.

Under Night In-Birth began development in 2010. The game's producer, Nobuya Narita, explained that development arose from the team's experiences working on Melty Blood, and a tentative remake of the game. French-Bread originally planned to work in high definition for the remake, but development later stalled while Type-Moon went on to work on Witch on the Holy Night. Early prototypes provided the foundation for Under Night In-Birth. Narita emphasized they wanted to differentiate the game from Melty Blood, so the lore, visuals, systems and combat flow are very different from the previous game. It marked the team's first game using high definition and hand-drawn high-resolution sprites.^[33] Due to the challenges they faced working in high definition with high-resolution assets for the first time, the French-Bread staff members frequently consulted BlazBlue game creator Toshimichi Mori.^[34]

A decade later, French-Bread and Type-Moon would eventually work together again to continue development on the Melty Blood HD remake project. With the studio's work on Under Night In-Birth serving as the foundation, the previously untitled remake was announced as Melty Blood: Type Lumina, which serves as a reboot to the Melty Blood series and as a tie-in to the remake timeline of Tsukihime franchise.

The PlayStation 3 version of the game received a 29/40 by Famitsu.^[42] Reviewers appreciated the ease of the controls but felt there was a barrier to entry and that the basics could be better explained.^[45] Kyle MacGregor of Destructoid said that it was "an intelligent, tactical fighting game that I'll surely be playing for a long time to come." Victor Ayora of IGN Spain said it was "One good fighting game. Maybe it's not as deep as previous Arc System Works games, but successfully achieves what it is aiming: to let the player enjoy it." Biagio Etna of IGN Italy lauded the art and combat system but criticized the steep learning curve and the pacing of the visual novel-style Chronicle Mode introduced in Exe:Late[st].^[46] Filippo Facchetti of Eurogamer concluded "an interesting 2D fighting game with a very unique fighting system. Just try it, and you'll be amazed." Exe:Late[cl-r] was nominated for the category of Best Fighting Game at The Game Awards 2020, but lost to Mortal Kombat 11.^[47]

• Skullgirls
• Melty Blood
• Akatsuki Blitzkampf
• Dengeki Bunko: Fighting Climax
• BlazBlue: Cross Tag Battle