In short/Fun Fact:

In Fierce Forces the summoned Characters, aka. The Comrades, (The Security Guards and other sentries accompanying Silent) have something called: Enhance Crystal Runes. Thanks to these symbols, being a part of the uniforms (or tattooed on the chest of Sentinel Martial Artist Sonic), the Comrades can summon their own assigned weapons.

In case of: Specialite Agent Shadow, he wield dual guns, which are also infused with the element of fire. Enhance Crystal Weapons are more durable and conduct an elemental power way better.

P.S. That's the Real: Shadow "Rely-On!" who has been upgraded to his Soldier Grandeur version, like Silent "Player-On!", and he is from the real world as well.

(In the Main Story Mode) The Fierce Duo work together, mainly on:
To stop Dr. Golden's "Prepare-Up!" invasion from Virtual World into their Actual World.
And to stop Imaginal Infinite, who in turn wants revenge on both of them.

Gotta go now.