From publisher blurb:
Rise of the Drow: The Commander of Malice is a D&D 3.5 and Pathnder Roleplaying Game compatible adventure that takes four to six 16th-18th level PCs to 20th level.
This adventure may be used either as a high-level standalone or a conclusion to the Rise of the Drow trilogy.
The war with the dark elves may well have come to an end on one plane, but it continues elsewhere in the multiverse as the prime instigator of the upheaval and unrest manages to escape. Souls are slippery items, able to squirm between the narrowest of cracks and evade the most thorough of enemies; one favored by a goddess seemingly holds the best of cards dealt by Fate.
After the final battle in the drow’s home, the party's foe once again finds an escape route and despair would be an easy emotion to feel—but the portal the villainous priestess used to evade the PCs after the final assault is still active, if heavily damaged, and restoring it gives one way to follow their enemy to wherever she has fled!
Pulses of sickly, acid-green light from pieces of the circle of stones tell the adventurers what their next step might be, but will they follow the fleeing essence of the priestess? First the PCs must prepare themselves after their recent hard-fought successes, and gather together the fragments of the gate to rebuild and activate it. Only then can they make their pursuit—that almost certainly means further effort from the party themselves, and possibly those around them. How many more sacrifices must those opposed to the drow make to defeat them once and for all? This may be the adventurers' final one, as they enter the home of the Queen of Venom for one final confrontation!