Fortress (要塞, Yōsai) is Fortress Brothers' Special Ninjutsu that involves Gunpla Creation.
Effects[]
Sakai and Mao could build a Gunpla in an instant. Sakai and Mao picked up a Kouki Gundam SD and tossed the contents into the air, pulled out his Clippers, and built the SD in a matter of seconds with Colored Markers. Sakai's rapid construction and glow effects when building Gunpla.