Melenis was a powerful Stormlord, and favoured wife of Meandor. She attack the dwarves at Deepmire, but was slain in retaliation.
At some point she created a phylactery, known as the Oscillator Gem, which was found under the ruins of Nirvenkiln by the humans Laryssa Mirabilis and Edward Portsmith. This gem was later entrusted to the halfling Karl Hushwick, who betrated the Keepers and resurrected Melenis. Reborn she found a number of potential necromancers and granted them powers, hoping to be able to use them in her plans to prevent Werlac opening a new Shadowgate. The most notable of these was the frostling Arvik.
Her ultimate goal as a lich was to end all life in Athla, and having accomplished this she would undo the magics that bound herself to undeath, leaving a completely barren world for any who might one day encounter it.
Relations with other characters:
As well as being a favoured wife of Meandor she appears to have had a relationship with Talic.
She teaches both Karl and Arvik, but should they both choose to become her harbingers of death she is happy to let them fight and keep the winner as her protégé, abandoning the weaker to his fate.