BlazBlue: Cross Tag Battle^{[lower-alpha 1]} is a 2D crossover fighting game developed and published by Arc System Works, first released for PlayStation 4, Nintendo Switch, and Windows in 2018.^[2] Cross Tag Battle features characters from different series, including BlazBlue, Persona 4 Arena, Under Night In-Birth, and RWBY.^[3] After the game was released, characters from Arcana Heart, Senran Kagura, and Akatsuki Blitzkampf were added as downloadable content. An arcade port was released in 2019 in Japan, a version for Amazon Luna was made available in 2021, and the Special Edition with all post-launch content was released for Xbox One and Xbox Series X/S in 2023. The game received mostly positive reviews, with praise for the visuals, music, online functionality and mechanics. However, it was criticised for lack of overall content at launch and DLC practices.

BlazBlue Cross Tag Battle is a 2D fighting game that puts the focus on tag team mechanics.^[4] In its main modes players battle in 2-vs-2 matches: they control one of the two selected characters at a time, and are able to switch between them on command. In addition to the standard fighting game meter that is expended to perform special and EX moves, the game features another resource: the assist meter. If they have enough, players can also have the second character use assist attacks to extend combos, keep the opponent away, or alternatively use all meter on "Cross Burst" to escape from dangerous situations. Similar to Marvel vs. Capcom, even if one character on the team loses all of their health, the match continues until both are down.

To accommodate for the tag mechanics and make characters easier to learn, the controls were simplified compared to mainline BlazBlue games and other participating series. In addition, each character was given some universal options, such as an overhead with the heavy button, invincible reversal attack, and auto combos.^[5] Some series-specific mechanics were retained, but heavily reworked to fit the game. Examples include the Persona system for the Persona cast, Reverse Beat for the Under Night In-Birth cast, or Reflector for the Akatsuki Blitzkampf cast.^{[citation needed]}

A singularity called the "Phantom Field" mixes reality with other universes. When the "Keystone" divides into four fragments, the female voice system known as "System XX" instructs one of the main characters to keep it away from others and reach the goal, gathering all characters to join the battle, who hope to separately return home to each universe. After all fragments merged into one, they prevent the system from changing the universe.

However, the next episode of the storyline ends with Hazama coming into possession of the primary keystone containing the system itself, and he attempts to use it to hijack the Takemagahara System. Takemagahara detects the remnants of Yūki Terumi within him, and copies his genes to create the clone of Susano’o as a countermeasure, but indirectly leads to the destruction of multiverse. While System XX holds off the clone from being unleashed, a regretful Hazama took over the role as the multiversal tournament’s conductor at the former’s behest. As System XX cannot hold off the Susano’o clone much longer, Hazama changes the contest that was solely Tag Battle-themed keystone hunting into multiple-themed stamp collecting, in addition to bring characters in from three more universes, hoping for the winners to assist him and System to defeat the clone. Despite the fact that the Susano’o clone was defeated by Ragna the Bloodedge and Naoto Kurogane, System XX cannot return the characters to their respective universes, due to being critically weakened from holding off the clone. The storyline concludes with the characters participating in the endless Tag Team-based Battle Royale while waiting for System XX’s full recovery.

In a 2016 interview with Forbes, producer^[24] Toshimichi Mori revealed his interest for Rooster Teeth and RWBY.^[25] Before the game was released, Rooster Teeth teased the possibility of a RWBY fighting game being revealed at Evo 2017 on their Twitter account.^[26] On July 16, 2017, the game was announced at the Evo 2017 championships following Ryusei Ito's victory in BlazBlue: Central Fiction.^[27][28] Ragna the Bloodedge, Jin Kisaragi, Yu Narukami, Hyde Kido and Ruby Rose appeared in the game on the announcement trailer.^[29] Konomi Higuchi served as a character designer.^[11] According to Mori, Cross Tag Battle was designed for home consoles, although the arcade version was later announced. The arcade port features support for USB controllers.^[30]

In an interview with Famitsu, Mori has stated that the game was developed with overseas audience in mind.^[31] Cross Tag Battle is the first BlazBlue game since Chrono Phantasma to be dubbed into English, with an option to toggle between English and Japanese voices on each character.^[32] Arc System Works published the game in most territories, while PQube released the console versions in Europe.^[33]

Pre-release, Arc System Works announced that there would be twenty paid downloadable content characters for the first season of the game, resulting in Cross Tag Battle launching with only half of its planned roster at twenty. This caused backlash from fans, with the arguments that the game reused assets from the past fighting games, and that half of Team RWBY would be sold separately.^[34] In response, Mori announced that Blake and Yang would be released free of charge.^[8][35] In addition, he stated that costs for the characters would not exceed that of the game's base retail cost.^[8][36] Post-release, Arc System Works revealed a teaser trailer for a fifth franchise to be included as part of Season 2, later revealed to be Arcana Heart at EVO Japan 2019. The sixth and seventh franchises, Senran Kagura and Akatsuki Blitzkampf, were revealed at EVO 2019.

At CEO 2021, it was revealed that the PlayStation 4 and Steam versions of the game were patched with rollback netcode in 2022.^[37] A version for Amazon Luna was released on February 18, 2021.^[38] At Tokyo Game Show 2022, it was announced that the Special Edition of the game, containing all post-release downloadable content, will launch for Xbox One and Xbox Series X/S in Q2 2023.^[39] It was released on April 26, 2023.^[40]

The game received mostly positive reviews, with praise for visuals, music, online functionality and game mechanics,^[41][42] but criticism of its lack of overall content at launch and its downloadable content (DLC) practices. Famitsu awarded it a score of 35/40.^[44]