Shield/Full Guard

"Argh, I fell for it! He made it seem like Full Attack and it was Full Guard!"

- Ken Satori on Kōhei Izumi

is the combination of two Shields, one through the Main and one through the Sub.

Appearance
Full Guard generally takes the form of two hemispheres stacked on top of each other. There is a small gap between the two strata, causing a chromatic difference between the outer layer (lighter) and the inner layer (darker). The more Shields are overlapped, the darker the color. Masataka Ninomiya and Yūma Kuga have used this technique through hexagonal Shields.

Abilities
As the activation of two Shields, Full Guard offers high defensive abilities. It can protect the user without drastically shrinking the total surface area, which is particularly useful when the attacker's location is not known. For this reason, if activated at the right moment, it is an effective way to flush out hiding Snipers. Like a normal Shield, Full Guard can be cast anywhere within about 25 meters of the user. Multiple agents can also overlap their Shields into one, further increasing the resistance of the resulting barrier. Since a Shield is activated both in the Main and the Sub, it is impossible to use other Triggers while in a state of Full Guard, making it a strictly defensive tactic.

Full Guard can withstand an Egret shot. Masataka Ninomiya and Kōhei Izumi, who have two of the highest Trion levels in Border, were able to block an Ibis and a Chelidon beam, respectively. In the former case, only the first Shield broke, whereas in the latter, both were shattered, although the blast was deflected. In normal circumstances, however, it seems to be impossible to stop Ibis even with Full Guard.

Users
See also: Shield users

There are at least 13 known users of Full Guard: Kōhei Izumi, Shun Midorikawa, Tsuneyuki Okudera, Tatsuya Kuruma, Kotarō Tomoe, Yūma Kuga, Rei Nasu, Masataka Ninomiya, Kai Minamisawa, Chika Amatori, Masato Kageura, Shinnosuke Tsuji, and Hyuse. However, since all but six A and B-rank agents have two Shields in their Trigger set, many more have the ability to use it.