Summoned by Umarak to wage war on the Okotans, the shadow horde was comprised of three different species: the Lava Beasts, Storm Beasts, and Quake Beasts. Each was born from a cloud of elemental energy, which several Shadow Traps of their respective element would jump into. Each Beast could regenerate if its Beast Mask of Corruption was left intact.
Initially, the brutal army of beasts made their first attack in the City of the Mask Makers. After some time, they were fought off by the six Toa, who discovered the army’s vulnerabilities pertaining to their regenerative masks. As the Toa began to drive off the beasts, the ensuing lull in the battle allowed a worried Ekimu to convene with the heroes, who decided to leave the city to the care of the Elemental Creatures.
Several days later, the six warriors faced a new army of beasts in the Region of Stone. In this second encounter, the beasts were defeated slightly quicker with the aid of a powered-up Ekimu.
Since Makuta is still trapped in the Shadow Realm, and hundreds of shadow traps still roam the island, there exists the potential for an new army of beasts to be raised,