Have you considered letting players play as ZOMBIES??? Here is how it might work, and it could be fun.

First, "player" zombies can only use PUNCH and BITE attacks. They need food to survive, but only eat HUMANS (raw, not cooked). They can either kill humans or find dead bodies (left after some other fighting??).
Zombies don’t use tools or objects but may use clothing.

If at all possible to program, a player playing as a zombie CANNOT leave the game and come back in later and still have “his” zombie character saved UNLESS, before exiting the game, he finds somewhere safe to hide. Exiting the game puts the “zombie” to sleep, coming back into the game causes the zombie to “wake up” rested. But it means his body is vulnerable while he is resting (unlike a human player whose character is safe until he/she logs back in.

BUT!!!! If, while the player is OUT of the game and another player finds the “zombie” asleep, that player can simply kill the zombie, and take its clothing if the clothing is any good and if he doesn't mind filthy smelly clothes. :)

If that happens, the “zombie player” is told, when logging back in, that his character was killed, and he gets a new one.

Players who play as Zombies SHOULD get some benefits from surviving and getting kills and experience!!! This could be, for example, letting their attacks cause more damage. Also, a zombie character ought to be able to customize their appearance in several disgusting ways eg, hacked off ears, rotten eye sockets, or entrails hanging out.

It could get to the stage where a very successful zombie becomes quite powerful and dangerous, and sets up his/her own territory in a village and defends it, while other players (hearing about this zombie) are forced to join together to hunt it down and kill it.

What do you all think?
Kimdownunder