BlazBlue: Entropy Effect is a 2D Roguelike Hack and Slash Action Platformer developed by 96Eyes for PC via Steam as well as iOS and Android. It is a Spin-Off of the BlazBlue fighting game series from Arc System Works and features the game's characters. The game entered Early Access on August 15, 2023 on Steam and was released on January 30, 2024.

The game is set in a futuristic world ravaged by a phenomenon known as Entropy Effect. To counteract the Entropy Effect, the MegaCorp SkysEyes has developed a training simulation program known as "ACE" to train the minds of the world's inhabitants to resist and cleanse the effects of Entropy. Within this digital realm, players of ACE, known as "ACERs", take on the form of heroes from another world to fight through ACE.

You take on the role of one such ACER who is enrolled in SkysEyes' Mind Training program. What appears to be routine training takes a strange turn when you happen upon a mysterious, shapeless entity that holds within it the power of Phenomena, fragments of the past found within ACE that hold within them the chance to alter the course of destiny. With the wheels of fate beginning to turn, it falls upon you to unlock the secrets of the Phenomena and unveil the truths behind SkysEyes and the Entropy Effect.

A major content update titled BlazBlue: Entropy Effect X was released on February 12th, 2026. Notably, this version added an expanded story that incorporates more details from the mainline BlazBlue canon into the storyline, such as featuring the reappearance of Naoto Kurogane in an as-of-yet unspecified narrative role.

This game contains examples of:

• Alternate Continuity:
  • The game's original plot (Sky City) is set in an entirely different continuity separate from the rest of the series, with the only connection between them being the characters used in Mind Training.
  • In Entropy Effect X's story (Lab), the setting is implied to be an alternate universe connected to the BlazBlue series.
• Ambiguously Evil: During your mission in the Sky City story, you hear rumors of a rogue ACER named Stan. He is known as a wanted criminal and is described as exceedingly dangerous, being blacklisted from SkysEyes on multiple occasions to the point where several legends around him have popped up, such as a story of him hacking SkysEyes and stealing millions of AP. You wind up bumping into him on multiple occasions (involuntarily, no less) where he is revealed to be a raving conspiracy theorist who believes that SkysEyes and anyone associated with it is evil; however, he doesn't display any particularly evil tendencies of his own besides having a few screws loose. After clearing Mind Challenge Phase 2, you get roped into an impromptu interrogation by SkysEyes' Security Bureau, where you have the opportunity to rat on him or protect him as a friend.
• Applied Phlebotinum: Entropy Particles are a key material to the game's original setting. They originate from the Entropy Ocean that surrounds the plateau that the game takes place on and their properties are as mysterious as their origins. The player discovers via the Phenomena that SkysEyes was conducting experiments with Entropy Particles at some point in the past despite the fact that they are supposedly difficult to transport in large quantities and dangerous to handle.
• Cast From HP: This, alongside Life Drain, is Ragna's primary gimmick: His Skill, Carnage Scissors, costs HP to cast, but heals Ragna if it connects, and many of his potentials grant him additional ways to spend HP for attacks (special mention goes to the "Blood Kain" potential, which applies this to all of Ragna's attacks). Ragna's Legacy Skill is Dead Spike, which pays 20% of the user's HP to shoot a projectile forwards that deals damage and heals the user when it hits enemies.
• Cessation of Existence: After attaining the fourteenth Shard of Possibility, Lime and Cafe both break down completely, with Cafe's cup falling and breaking in the aftermath. While Doctor Mercurius initially ordered you to remain silent, she comes clean and explains that the Shards could be used to reshape reality, and it remains their only chance of getting the two back. DB takes over their functions in the Lab hence. After the fifteenth, Fox goes, too, and Ti's next request is maxing out six Mind Crystals under the fear that it will be the last thing he can do before he disappears too... which he does after the sixteenth Shard and one last cup of coffee. Dr. Mercurius leaves a message and gives you one last debriefing before she goes after that, leaving you and DB to track down the last Shard.
• Counter-Attack: Kokuujin: Yukikaze (Empty Sky Form: Winter's Riposte) is Hakumen's Skill and has him generate a shield in front of him. If an enemy attack strikes him from the front while it's active, Hakumen will block the attack and transition into an invincible counter that slices through foes for heavy damage. When passed down to another character via Legacy Skill, the skill becomes Kokuujin: Jinrai (Empty Sky Form: Spring's Thunderbolt), where the user creates a glyph that renders them momentarily stationary; if the user is struck while the glyph is active, the offending attack is nullified and the user calls down a powerful lightning strike. Jinrai is also available for Hakumen as a Potential, and is easily his most damaging attack.
• Dash Attack:
  • Most characters have the ability to perform a unique attack by inputting Basic Attack while in their dashing animation. Some can also upgrade this with Potentials to boost it or alter its effects.
  • Hakumen's dash is unique as it has a hitbox and can strike foes by charging into them with knockback. As a tradeoff, Hakumen's dash lacks invulnerability frames by default and can only gain an invulnerable dash by claiming a specific Potential.
• Door to Before: In Area Omega, there are several warp points scattered across the map that will activate once you pass through them. You can use a warp point to travel to any other unlocked warp point, saving you time backtracking when you need to go to a previously visited area such as a shop or boss room.
• Final Boss: Clear the Elite Sample of Area Omega, and you get to challenge the Ultimate Sample and final boss of Mind Training: Susano'o. Additionally, once you've completed all the Mind Uploads, you can face the Ultimate Trial: Susano'o again, but this time with a third phase that mimics the 2D fighting games.
• History Repeats: After recovering a Shard of Possibility that depicted Lotte Carmine's attempted jump into the Boundary, Cafe decided to try to jump into the Sea of Possibility himself, despite the fact that everyone knew only Ace could do so safely. His mind got violated by the mere attempt, but Doctor Mercurius managed to stabilize him, albeit with amnesia about that one moment.
• In Name Only:
  • Originally, the only connection this game has with the core BlazBlue franchise is the use of its characters, who are also completely plot irrelevant and can be functionally replaced by any arbitrary collection of characters. Everything else, including its setting and plot, are completely new and have no connection to anything else in the series.
  • The Entropy Effect X update/release averts this with the Lab story line which ties into the BlazBlue mythos.
• It Only Works Once: A single Evotype can only be used once in a Mind Challenge. Once it is used, regardless of whether or not you won or lost, that Evotype cannot be used again. This will eventually force you back to Mind Training to create a new Evotype to replace consumed ones.
• Macrogame: Several forms, in fact.
  • Playing in ACE or DBS rewards AP or DP respectively, which are a currency spent to unlock Mind Upgrades and attempt Mind Challenges. Mind Upgrades are permanent effects that apply persistently in ACE once unlocked, while Mind Challenges are "boss" stages that reward Prototype Analyzers and other rewards for completion. Recording a certain number of Tactics in Mind Training will also give AP bonuses.
  • Each time you finish a run in ACE or DBS, your character progress is saved as an Evotype (Optimized Avatar in "Entropy Effect X") with an assigned Rating. In Mind Training, up to two Evotypes can be used to pass down Active Skills and Legacy Skills based on their Rating to subsequent runs, powering up future characters. In Mind Challenges, you must attempt each Mind Challenges using a saved Evotype, which require an Evotype of a high enough Rating to unlock and will give you the character you played as with all of their upgrades and Potentials to fight with.
• Metroidvania: Once you clear three areas in Mind Training, you unlock access to Area Omega where, unlike the self-contained instances used in the normal stages, you play through a sizeable randomly-generated open-world map where you are given free reign to explore. Here, further character progress is achieved by using your remaining Exchange Points to buy from the shop and seeking out treasures that grant a substantial EP and AP bonus. In addition, there are two more major encounters here to complete your run: a miniboss Elite Sample and the Ultimate Sample.
• Multiple Endings: Mind training always concludes the same way - with a fight against Susano'o - but the main story has multiple endings.
• Mythology Gag:
  • Losing to Susano'o while playing as Hakumen or beating Susano'o as Ragna both award a unique achievement.
  • Likewise, losing to Arakune as Kokonoe will also unlock a similar achievement.
  • During the final phase of the Ultimate Trial the health bars from Central Fiction replace the HUD and the camera zooms in to mimic the presentation of the Blazblue fighting games.
• Mighty Glacier: Hakumen is relatively slow to move or attack, but to compensate he hits extraordinarily hard, has very high starting HP and he starts with a damaging dash and a block and counter move
• New Game Plus: Finishing the base/mobile version's storyline will permanently lock you out of other endings on that playthrough. However, you can "Inherit" your Prototypes, Evotypes, Mind Upgrades, and Crystals to a new save, and unlock the other storyline depending on the version you're playing in X.
• New Work, Recycled Graphics: The sprites and assets (such as Japanese voice work) for the playable cast is reused from their appearances in BlazBlue: Central Fiction.
• Sprite/Polygon Mix: All assets in the real world are rendered in 3D. In ACE, characters and enemies are 2D, but the background and setpieces are in 3D.
• Starter Mon: The base version starts you off with Hibiki Kohaku, and you need Prototype Analyzers to unlock the other characters. Entropy Effect X starts you in a tutorial stage with Hibiki, but after that, you get an Avatar Analyzer which you can use on any BlazBlue character you wish.^note The Prisoner and ICEY require special Analyzers before you can play as them in the main game.
• Suspiciously Similar Substitute: All of the new characters featured in Entropy Effect X bear deliberate similarities to the members of Sector Seven, right down to their initials and voice actors. Some Shards of Possibility linked to these characters yield profound reactions to the associated doctor. After the sixteenth shard, just before she goes, Dr. Mercurius reveals that she is a replica of another professor, likely Kokonoe, who made data replicas based on her other associates.
  • Dr. Mercurius is the substitute for Kokonoe, being a feline humanoid who acts as the group's leader.
  • Dr. Ti is the substitute for Iron Tager, sharing his stern, yet gentle nature and loyalty towards their feline boss. He resonates rather intensely to a Shard of Possibility depicting Noel's first encounter with Tager.
  • Dr. Lime is the substitute for Litchi Faye-Ling, sharing her occupation as a healer, her beautiful looks, fruit-themed name, and kind and caring personality.
  • Dr. Fox is the substitute for Kajun Fayecott, being a purple-haired, knowledge-driven researcher who wears a butterfly hairclip and an outfit similar to Kajun's Military Academy uniform and has a particular soft spot for an unknown friend like Kajun has for Mai. She exhibits unusual behavior after encountering a Shard of Possibility where Makoto properly introduces herself to Noel and Tsubaki.
  • Dr. Cafe is the substitute for Lotte Carmine, being a black-haired, bespectacled scientist who is extremely dedicated to his research to his own detriment.
• Tomato in the Mirror: The entire cast of X are actually alternate copies of characters from the main franchise, and were all created by Kokonoe as a backup plan in case Ragna failed to stop the plans of Izanami and later Susano'o. By the end of the game, the replicas suffer Cessation of Existence due to Ragna erasing himself and creating a new world in place of the old one to allow new possibilities to be born and observed.
• Voice with an Internet Connection:
  • In the Sky City story, you are accompanied by a female handler from within SkysEyes who is meant to assist you with the Mind Training program. However, once she learns about the Phenomena and how they provide visions of the past, she deviates from her job and decides to help you investigate SkysEyes to see if they're up to something shady.
  • In the Lab storyline, your runs are accompanied by an AI companion programmed to assist you. As staff disappear from the lab, it takes over their operations.