So, I have completed the sketches for all the "components" for my design. In this sheet I've define the color scheme for it, including some FX. The little face inside the skull mouth is that of Morrigan her self, as her spirit inhabits the artifact. When the cauldron is used to cast a spell, she "awakens" and the FX are triggered.
Originally, I thought in using blood for theCauldron's content but that, in addition with the skulls floating inside the potion, seemed to me far too gory. So, I decided to change it to a ghostly green. After all, Morrigan is often translated as "Ghostly Queen", so, it suits the concept.
Now, I can start working in the concept sheet and the illustration... n___n