Oni Twins Ramba & Biranba

Lore
The red elder sister Ramba and the blue younger sister Biranba were fiercely loyal to their leader Yakushana. It was not a particularly tested bond, for they would have wreaked havoc regardless of command. Even so, the oni were social and thus knew the value in maintaining relationships. "That human looks pretty tasty. Be sure to save him for the boss, Biranba."

Acquisition
Ranking Reward in the Onigashima Nightmare Odyssey Event.

Name origin
Oni (鬼), translated as demons, devils, ogres, or trolls, are characters from the Japanese folklore.