At some point im planning on having my players return to locanthos the idea being that the crow father since the events of illumination has been corrupting seth the voice seths warband is now a cult to the crow father and is a threat not only to other warbands put also port suffering but im struggling to generate a host as surely most the high level psykers will either be on black ships or executed (explaining why the crow father needed Aristarchus any input regarding my problem or any suggestions for the scenario would be greatly appreciated.

graycrow said:

You assume that this is the reason. This assumption of yours is hindering you from coming up with a goog and entertaining plot.
Thereby, I advise not to assume it . There is only one point of imperial presents on entire Iocanthus. Port Suffering. I would take this as an assumption to the contrary: there cannot be any harsh control of the psykers. How could it, with the population being in desolated settlements and/or in rowing warbands? For sure, a psyker can go undetected by the imperium if not for his/her own people turning him in.

Talking reason/plot:
I would not take "Seth the Voice". Yes, it where his voicers whom stormed the cathedral and it were the Ashleen who have been the good guy...but remember, the Crow Father was a "god" to the natives a long long time ago (before the Angevuin crusade).

Perhaps, some of the Ashleen who where wittness of the events at the Cathedral (and survived it!) where quiet impressed.... now seeking out people knowing about the old ways. Isn´t the fact that this entity existents which the Imperium believed crushed by one of there saints times and times ago a proof that the Emporer on the very distant Terra isn´t half that powerfull as they have been preached?

The Crowfather could still use some voicers (still being the crazed maniacs that they are who are searching for "revelations") to turn the attention of the enemy to them...even sending them against the Ashleen... so that his "true" followers better go unnoticed. After all, it was told be the old hag Rain that the Crowfather was used to turn people against each other in battle and slaugther. ...

Gregorius21778 said:

The Abbey of Dawn is also on Iocanthos, I think an Soritas Abbey counts as an imperial presence.

Talking reason/plot:

I would agree that Seth the voice is the wrong choice for an antagonist in this instance.

Maybe make up a tribal chief with a medium sized army that has moved into the area of stern hope and has become corrupted by the whisperings of the crow father.

Or perhaps Skull is slowly destroying rival warbands around Port Suffering preparing to launch an assault on the port and claim it for himself and the party have to find a way to stop him and save Port Suffering.

Or perhaps a group of mutants escaped here with from tranch where they were part of the Pale Throng and now all the outcasts and mutants on Iocanthos that usually get hunted down quickly as they live in small groups are massing under their banner in secret. You only suspect this due to the large decrease in the black ship tithe in recent months.

If you are struggling to come up with a satisfying host for the demon, why not assume that it doesn't have one yet: the description of Tsyiak emphasises that he works through deception and lies so he could still be a dangerous presence in an adventure even without having a physical form. If your players have already defeated him once I would be tempted to make the adventure about Tsyiak's desire for revenge against the acolytes who thwarted his last attempt to manifest on Iocanthos. Perhaps the machinations of the warlord (or Seth if you decide to stick with him) are about creating enough of a mess around Port Suffering to attract the acolytes back to Iocanthos, because Tsyiak can't use just any host; it has to be the one who landed the killing blow last time (assuming you can remember which of your players that actually was).

Gregorius' idea about the demon misdirecting the interest of the acolytes might mix well with a setup like this. You could even go so far as to have the demon trying to manipulate the players into killing someone important or a group of significant individuals for him as the final sacrifice. Given that the players are likely to be on the lookout for Tsyiak round two as soon as they realise you're sending them back to Iocanthos, you might get more mileage out of a scenario that manipulates these expectations than you would out of trying to make Tsyiak the hidden power behind a disturbance. The adventure would then be about the characters trying to figure out who is really a servant of the demon and who is just an innocent dupe, as it becomes increasingly apparent that killing the wrong guy will result in disaster. You could increase the tension further by throwing in a time constraint, for instance by having an apparent ally of the acolytes revealing that an impending astrological conjunction will allow Tsyiak to amnifest if they don't kill his chief servant first, or by making them think that Tsyiak intends to strike during an imminent and crucial set of treaty discussions, etc.