Riku Kuroi is a Water unit making her debut and, for the time being, her only appearance in Gacha World as a 5-star unit who was one of the winners in the first "create your own character" contest. She was created by Shaznay C. T.
Her active skill is called "Bullet Buster" in which she would fire multiple explosive rounds at the back row of enemies, doing water damage. Her leader skill is "Critical Ultra Boost" which increases the crit chance of all attacks by 15%.
Riku's sprite from Gacha World