The shield can be equipped to defend the player's front and perform a melee attack, as well as defend from the Dragon's fire breath as well as damaged caused by the Gigant Eye Beam Trap. The shield also features a melee attack which sends out a giant green fireball to damage zombies. It can be used a total of three times, similar to the rocket boost from the Rocket Shield.
It's possible to upgrade it into the Tiamat's Maw by completing two of the trials on the map Gorod Krovi: one is to survive the dragon's fire for its entire duration, requiring the wielder to stand in dragon fire for the full duration a minimum of two times, whilst having the shield with them. An audio cue will be heard when this is done. The other challenge is to kill around 50 zombies with the shield; the player may use either the melee or fireball attack for this. Once this is done, another audio cue will be heard.
The second step is to shoot three symbols that are around the map, with the Guard of Fafnir. One can be found at the Dragon Command Center, to the left side of the left hangar, on a wall. Another can be found at the Supply Depot, opposite to the ramp. The third can be found at the Tank Factory, on the right shoulder of the fallen robot near the hangar.
After this is done, the shield must be placed in the remains of the dead dragon in the spawn room. The shield will be dipped in the puddle of blood and will come out upgraded.