[Taqwus]

There's also at least one way of remotely inflicting horror marks on people -- Horror Seed -- although the odds of nailing a pretender with that are probably fairly low assuming a decent escort, and this can be made more difficult via dome spells.

Stumbling onto and getting unlucky with a Vale of Infinite Horror, or getting unlucky after killing somebody who's B9-blessed, might also be problematic.

But yes, if you're in battle, being smacked by a dozen Seithkonas casting Nether Darts or fending off F9W9 Helhirdings might be a more serious concern...