They appear on Tier 1 maps at wave 22 and on Tier 2 maps at wave 25. On Tier 3 maps they appear at wave 9, shortly before the second juggernaut wave in which they will plant several Claymores. They also appear on Tier 4 maps at wave 17. They place claymores around the map. When they assault the player, they are usually reckless. Unlike other enemies, they do not appear to be able to throw grenades. They are also armed with the PM-9submachine gun. The Claymores can be seen by the player(s), and do significant damage to the player, where two will be enough to take them down without armour. They grant the player $150 upon death. Enemy Claymores are sometimes placed in plain sight of the player, and in spots that a claymore would be very much impractical.
Enemy Claymores are usually set down by armories and nearby the player's location. Also, they have a particularly large range compared to their multiplayer counterparts and unlike the Claymores the player can plant, the Claymore Experts' Claymores have a 360 degree blast radius, but there is significantly less damage dealt from behind the claymore than from the front.