On the surface this is an ordinary quest: the group walks the route and completes the checkpoints as usual. Underneath, one participant has been chosen in secret to end the walk for everyone else.
Killer on the Road is a conversion: build or open a standard quest, then change its mode from Edit Quest. Everything you already made stays in place, and checkpoints are completed the normal way.
When the match starts, one participant is secretly chosen as the Killer. Within a twenty-metre radius they can eliminate another player, and nobody else is told who they are.
Survivors are not defenceless: anyone can accuse the participant they suspect. The game ends when the Killer is accused, or when every other participant has been eliminated.
Chosen in secret. Can eliminate a participant within 20 metres.
Keep completing checkpoints, and accuse anyone they suspect.
When the Killer is accused — or when no one else is left.