Strength for Another

Sakura, Nirei, and Suo are called up to the roof of Furin High School. Waiting for them are the Four Kings, their next-in-commands, and Sugishita, who's helping Umemiya. Having heard about the recent events from Tsubakino, Umemiya has called everyone here to tell the story of Endo, who was the mastermind behind the conflicts between KEEL and GRAVEL, and to explain the origins of the Bofurin unification. As Umemiya, Hiragi, Tsubakino, Momose, and Mizuki join Furin High School and become a part of the Bofurin; what shadow is born as a result of this?