Bitter Blood

This is most interesting and confirms some of my own studies. Vampirism is spread through a bloody bite. The strigoi and necrarchs studied this quite intently and it is suspected that they spread this curse to some of the creatures who inhabit these marshes. No, you will not turn into a vampire if a bat bites you, but bats biting other bats is suspected to have such an effect, or at least the Peregrine Squire suspected as much. As far as my research understands, blood sucking creatures hold their own contaminated blood in sacs behind their fangs. When they bite their victim, their own blood is secreted through the fangs into the victim. Bring me these blood sacs and it will help me study the effects of this bitter blood. Take this list of creatures and consult it. Try not to hack and smash the creatures to bits, or else it'll be hard to find solid blood sacs. They are rather delicate and a heavy hand will rupture them.

Travel out of Beardrot and search for Neborhest Bats. Kill them until you kill one gently enough to acquire its unruptured blood sac. Consult Ralla Widmer's list in your quest inventory for the next creature to kill.