Grendel

Grendel is an alchemist who'd been in a little magical accident.

When the Avatar found a talking Giant Rat in a hut south of Cove in Ultima V, the confusion was great for some moments. Turned out that the alchemist Grendel had tried to find a spell to turn beings into rats. His spell however worked to well, turning him into a rat. Still he didn't drown in despair and after some refindement, he'd perfected a spell that would temporarily turn a being into a rat.

He was willing to share the secret with the Avatar, sying that the 6th circle spell would need Spider Silk mixed with Sulfurous Ash and the incanation REL XEN BET to put the spell into effect.