The new girls introduced this event [v3.2] are: Mia - Starchaser (<-- click to go to her article) Click here for my take on how Starchaser affects the game and its meta.
Haru - Raikou      (<-- click to go to her article) Click here for my take on how Raikou affects the game and its meta.
Raikou is freely claimable between the 27th of November and the 18th of December by competing her puzzle collection game