The Mutants that were engaged with the enemy Androids were all ranged attackers, the ones that Jiang Fei and the martial artists were currently attacking. Most of the melee attackers were all on standby. Hence, when Desir gave the order to attack the martial artist, Marcus was able to quickly gather a small army of Mutants to attack Jiang Fei.
One after another, the Mutants morphed into animals such as lions, bears, and other predatory animals to charge into the fight. There were other non-beast forms such as changing their outer body into rocks and metals. Others could liquify themselves, turning into mud, water, and intangible forms that were immune to physical attacks.
Fueled with intense hatred toward the other, both sides charged and clashed with attacks flinging with the intention to kill.