The Ballad of Adler Young, Canto 2.5

Upon returning to the lowfolk world, discover that the rabbits had left the area. With the exception of the sacrificial maiden, who still refuses to be left unsacrificed and Percy, who is now tied to a second stake next to her.

(Mystery Elf) Turn out to be two elves, a hulking one, and a much smaller one.
(Hulking Elf) Wonder where your froggie George has gone.

The smaller of the elves coming for the sacrifice, be a hunchbacked rat wearing goggles and a lab coat. Keep scolding the other one and telling him that "the Master" is most displeased with the loss of the retrieval frog. But change your opinion once you discover not one, but two sacrifices ready.

The bigger elf, have the intelligence that makes Fifi (almost) look like a genius by comparison.