Fortress

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.