Oh, dear. You’ve pissed off someone whose concept of “eternal grudge” could be taken literally. Essentially, you’ve got the Enemy Flaw with a powerful and more or less immortal entity: a vampire elder, a demon, a demigod, totem spirit, Loa, dragon, or other being who measures its existence in centuries or millennia, with resources and abilities to match. Foolish wizard, what will you do now?

For the relative power of this enemy (or perhaps for the number of your enemies), see the Merit: Powerful Ally, p. 77.