This reminds me of a Starcraft: Broodwar custom game that had a similar theme which may be possible to be implemented in ZK.
It was called Phantom and the basics of it were:
- An FFA, probably best between 3 and 8 players.
- All players start off allied and have full vision of each other, with the ability to unally and turn off vision share.
- At some point early in the game (~1 minute) a player is secretly informed he is the phantom.
- The phantom wins by killing all other players, all other players win if the phantom dies.
- From this point onwards the phantom gains extra resources (in ZK could be done by a resource multiplier based on the number of players in game?).
- The phantom will need to start spending his extra money at some point to take out opponents, but they'll all be watching each other closely.
- After a certain amount of time, the phantom is revealed to all. This is to stop the phantom just playing as if he didn't have extra resources and dragging it out into a long boring game.
Here is a thread on one iteration of it I found in Starcraft
https://tl.net/forum/brood-war/59882-new-ums-map-phantom-ultimate