Summoners are an uncommon enemy type in Zombie Army Trilogy.
They were generals of the German Army that seemingly died from a head injury, as they have bandages wrapped around their heads.
They are not directly hostile towards the player. However, they have the ability to spawn groups of enemy zombies, and are even capable of reanimating defeated ones, thus making them a high priority target.
They can only be killed with headshots, and will not even notice damage done anywhere else. Until they are killed, they will spawn enemies infinitely, and can cause player to waste a lot of ammo if they are not defeated promptly. Summoners move their heads around constantly, making it difficult for the player to land a headshot.