UGH! GROSS! WHAT IS THAT?!
The result of too much shifting, that's what.
In response to the outbreak of elves, the dwarves put forth a sacrifice to sculpt with fey energy they collected from fallen elves. The result was... imperfect. The kinetic energy from this forging destroyed most of the dweomer buildings, leaving few alive to defend against the onslaught of elves.
The Stone Dwarves stood their ground to their last breat. Duende, however, chose life. He shifted into an elf warrior, infiltrating their ranks.

After learning all he could on shifting from the druids of some unimportant grove, he slaughtered them all in his dread lord form-- cackling. Not a single elven weapon could scratch him. The woodland animals were helpless. The druids escaped to preserve their culture, and thus...

Duende of the Woodforged looks for these druids to claim retribution for his clansmen.