Spirit traps are at this time believed to only be found in DL3. Polydectes said that these devices operate counter to the "Devil's" (Believed to be the Last Seraph) wishes, and that it is ironic she is now forced to power them. the reasons for this dislike of spirit traps is still unknown, but may be linked to the creation of soul stars and Illborn.
A spirit trap pulls a spirit (a player) out of the collective and forces it to fight. The corresponding player can attempt to break free; if the roll is successful, the player can now act on their own. However, the spirit will begin to fade after some time. The only time observed was after finishing the fight and leaving, but it may be possible to begin fading during the fight if it drags on long enough.Once a spirit begins fading, they make a roll to resist it each turn. On failure, they vanish.
There is also a variant of spirit trap, known as an arena trap. It has been seen once, and summons more spirits than a normal trap.