If you're playing BlazBlue: Cross Tag Battle right now, you're probably wondering when the game is going to fill out the rest of its roster. It launches with 20 characters from BlazBlue, Persona 4 Arena, Under Night In-Birth, and RWBY, but the full roster is slated to eventually be 40 characters.
Some of the downloadable content (DLC) is available right now: one free pack with Blake from RWBY and the first of six Character Packs, offering three characters—Platinum from BlazBlue, Kanji from Persona 4 Arena, and Orie from Under Night In-Birth—for $4.99. (Free for the first two weeks.) Alternatively, you can purchase the All in One DLC Combo pack for $19.99, giving you access to all six Character Packs.
Arc System Works has promised that the roster will be 31 characters by time Evo 2018 rolls around on August 3-5, 2018. The studio has yet to give a firm release date for the other Character Packs though.
Blazblue: Cross Tag Battle Deluxe Edition on the Nintendo eShop is offering a little detail. The Deluxe Edition includes all of the planned DLC and on the eShop, publishers can give estimated release dates for future content.
RWBY's Yang will be a free download alongside Character Pack 2 (Jubei from BlazBlue, Aigis from Persona 4 Arena, and Carmine from Under Night In-Birth) and Character Pack 3 (Hakumen from BlazBlue, Naoto from Persona 4 Arena, and Vatista from Under Night In-Birth) with an estimated release date of June 19, 2018. Character Pack 4 is currently scheduled for August 6, Character Pack 5 is scheduled for August 21, and Character Pack 6 is estimated to release on September 4.
All of these release dates are estimated, but fit with the timeline given by Arc System Works.