Dragon's Blood
So powerful is this creature that the blood burns as if aflame. Precise measurements of this are wise, for too much and the magic will go dangerously awry.
Originally appeared in Ultima VIII: Pagan as a Thaumaturgy reagent, it was to have been used in Ultima Online as a reagent for the (originally canceled) Necromancy system. On most shards it is now a rare item, part of a set commonly called Pagan Reagents (
Image of Dragon's Blood as a Thaumaturgy reagent).
With the Ultima Online: Stygian Abyss expansions release, Dragon's Blood is now a Mysticism reagent. It is also used in certain quests in Ter Mur such as Ortlem the Mystic's A Mystic's Journey quest ( 
Image of Dragon's Blood as a Mysticism reagent). It can be obtained by skinning: