Bronya Zaychik was a Russian orphan who was raised as an assassin since she was young due to the aftermath of the 2nd Houkai War. Eventually she was sent to assassinate Cocolia, a member of Anti-Entropy, but failed in her mission. Instead of killing her, Cocolia took pity on Bronya and took her to be raised in her orphanage. There Bronya was experimented on, gaining the power to use Houkai energy, levitate, manipulate Remodelled Bunny 19C, and more but lost her emotions and the ability to use he