Fighting Fantasy/WMG

In Deathrap Dungeon, the Ninja set many of the traps

 * Since the Ninja is the only one of the contestants confirmed to be evil by attacking you outright, and he is a Ninja, it's possible - if not probable - that many problems you have beforehand are his work. He probably left the backpack with the black widow spider in it, he definitely set up the gas trap in the chest after taking the diamond from it, and he likely wrote the sign saying, "No Weapons Beyond this Point", as he waited to ambush anyone who actually did so. This is guy is a proper practitioner of Ninjitsu.