In my game, I treat them as followers. They also act as very, very obscene AP sinks for LOSSES. The leader can't bid anything he doesn't have but he can use them to soak his lost AP. However, since the Zombie is going to be getting damanged, it may simply function as a multiple attacker. But it DOES make facing zombies a bad show.
That's why Humakti have Kill Undead Thing. I allow THAT to chop zombies up more effectively -- when they go below 0, they suffere regular results.
Conversely, I could say that when they go below 0 AP , they drop out of the follower pool but still count as an opponent -- they can bid their non-existent 5 AP until they get to the incapacatated state and just flop around distractingly (giving that -3 opponent penalty)
A clever foe will pay the AP to go LAST after all the zombies have flopped around and attack the distracted victim with a hefty penalty already. It works on those annoying combat monster types. =)
Jeff
Powered by hypermail