Ok, so I've run a mission where the team are investigating rumours of a sorcery cult in a hive cluster. The player's contact turns out to be a sanctioned psyker gone rogue who is orchestrating the whole deal and, naturally, he has set a trap for some inquisition acolytes…

the reason he has set the trap is so he could dump them on to a feudal world, without their memories, where there are many psykers hunted in a standard feudal witch hunt. The point is that the rogue psyker needs the acolytes to befriend the psykers and protect them, maybe constructing their own community, so eventually, the rogue can come back with an army of psykers that he can train and use for his own use.

The idea is the acolytes are trying to discover what's happened to them whilst going through the whole thing of protecting the psyker cult they've been dropped in to.

What I want to know is whether it is plausible to have psykers on a feudal world, not sanctioned by the imperium, on the grounds that it is a feudal world and without technology they are no threat because they are confined to one planet?

Every imperial World is visited by the Black Ships, no matter if it is a hive or feudal world. Even on e feudal world, where technology is rare but hast not to be non-existant, the Imperium has made up some laws that include their policie for psykers. They have to be gathered and impriosioned until the black ships arrive - or to be killed. Though it is quite dificult to identify these individuals the black ships bring equipment of their own and are quite rigid with their only and most serious task.

The only thing is that the frequenzy of their visits is quite unpredictable but if I remember right they have to visit every planet at least once in a hundred years. By this procedure they root out the psykers wich are are quite small population and prevent them from gathering or even developing or improving their own potential. Many weak psykers die withoutout knowing of their powers but the stronger and therefore dangerous one can be identified with a realy good quote. Also some feudal worlds still have their imperial bureaucracy like the administratum and arbites and with them you need some infrastructure like an imperial chor of psykers for some tasks like long range communication etc. Many times it is this institution that identifies psykers before the black ships arrive.

And more specific to your question:

Wardzy dude said:

By imperial law there is no excuse for allowing an unsactioned psyker to live. Common policy is to kill them if no forces are available that are trained to deal with them. A psyker is allways a threat and just because there is no regular ship traffic that can take him to another world there can always be a smuggler or what ever. Also this psyker could harm the world on its own. Deamon infestation is just an extreme thing that might happen but also he can destroy the whole hierachy that is paying tributes to the imperium. By no means unsanctioned psykers are tollerated, they are always heretic by imperial definition, they are a witch, an abomination. If there is a powerfull indiviudal that tries to hide them on a distant world that might work but when the black ships arrive they will notice this cult and annihilate it. So this cult might be only 100 years or 4-5 generations old.

Thanks, this has given me other ideas to use