I'm musing on what effects a location with strong Dhar build up should have (sparked by 1000 Thrones campaign but generally useable).

This is not a simple "bit of dhar" but a tainted spot such as blocked waystone or other "pool of dhar". The black corrupted magic of death and decay is like a corrupt oil that lies upon the surface of the normal winds of magic. The winds are still present but dhar is there, and there "first". To reach the winds or let them reach you (depending on chosen metaphor) you must "reach through a film of this rot" or "risk letting it flow into you too". That is the idea behind the following.

Suggestions to improve?

I'm looking for something a bit different from warpstone/corruption though fine to have a bit of corruption threat worked in.

DHAR'S BLACK TAINT

This area is permeated with Dhar magic, the power of death and decay.

Physical Actions Gain:

Chaos Star: An item rots or corrodes - Damaged condition.

All Actions Gain:

Two Banes: Fatigue and Futility - 1 Fatigue and 1 Stress and adjust stance 1 step to Neutral

Spell Actions:

Users of Dhar gain 2 points if below Equilibrium (instead of normal 1) and gain a free Expertise Die on channelling.

Users of untainted magic find the winds difficult to draw on. They add Challenge Die to all Channel rolls.

Spell Miscasts cause a Corruption check (equal to number of Chaos Stars plus one) in addition to generating a normal Miscast card draw.

sounds reasonable but I think the additional effects to the miscast is a bit hard.

Imo a corruption check equal the count of chaos stars might be enough.

dunno about your players, but since they are at their 70th+ advance, how do their characteristics look like?

have they upped all theirs to 5/6? then I would understand the +1 chaos star to make it more challenging.

My PC's generally have their prime stats at 6 (except for Father Erich who has split being fighter and priest). I added one to Corruption check because there is no such thing as a 1 Challenge die corruption check in the core rules.

I was pondering that, perhaps just trigging corruption check on two chaos stars. That becomes the actual use of the stars then (recall that Miscast results don't absorb the baseline use of chaos stars).

Rob

I was looking through the Dhar Thingy in TTT and figured that it is really bad ass stuff that is going on there.

I think your initial solution sounds reasonable.