You gave me parameters to work with and here’s the connected dots…
Surge of the Graveborn undead animation affected at Tranmere within a few years, especially the graveyard; Its population is 300-400 x3 transient; It is close to The Red March and not at The Autumn Wall directly but nearby; Would be stragglers only.– Use the Surge of the Graveborn to key a year your adventure occurs.
– See Tranmere for the location you want and history. .
Justicar option – to re-hallow the ground? msg has to go out and come back but people keep dying, clergy cannot find it; Godric Hammerhand at Tower of the Exiles might be better – he is farther away and not a Justicar exactly. Find a reason the Justicar at Fortun is busy – its close by.