Many times throughout the series, stronger variations of enemies have appeared; many times, these foes are Crimson in color. These come in both officially mutant and non-mutant varieties. They appear in nearly every game, although they do not appear in Earth Defense Force Insect Armageddon -- instead, "Ravager" versions of the buggernauts appear.

Monster AttackEdit

Global Defence ForceEdit

Earth Defense Force 2025Edit

Earth Defense Force 2017Edit

Earth Defense Force 2025Edit

Earth Defense Force 4.1: The Shadow of New DespairEdit

The Shadow of New Despair, while being a remake of 2025, does include numerous new crimson foes to contend with. In the single-player or cooperative player mode, the players face Crimson Hornets, Crimson Dragons, Crimson Death Queens, and a Crimson Erginus. Also in the online multiplayer missions, Dark Red Ants (a further stage of the Crimson Ants) appear.

The Crimson Gunships and Crimson Ants from earlier games still make their appearances here as well.