Promise of the Witch-King

Promise of the Witch-King is the second book of The Sellswords trilogy by R.A. Salvatore.

"The book was hidden well.

Its pages promised the power of the Witch-King himself.

And now that it’s been found, even the fact that it kills anyone foolish enough to crack its cover won't stop people from fighting over it.

Welcome to the Bloodstone Lands!

Human assassin Artemis Entreri and his dark elf companion Jarlaxle have come to the demon-haunted wastelands of the frozen north at the request of their dragon patron. It doesn't take long for them to find themselves caught in the middle of a struggle between powerful forces that would like nothing more than to see them both dead... or worse.

But Entreri and Jarlaxle aren't just any wandering sellswords, and the ancient evils and bitter blood-feuds of the wild Bloodstone Lands may have finally met their match."

Summary
In Damara, Artemis and Jarlaxle battle and kill a lich named Herminicle in an animated tower while barely escaping with their lives. The companions then travel to Vaasa at the request of their employers, Tazmikella and Ilnezhara. They seek artifacts of the infamous lich Zhengyi. A half-orc named Arrayan finds her way to an ancient tome of Zhengyi and unwittingly starts a self-creating castle, one similar to Zhengyi's former Castle Perilous, to come into existence.

With her health continually being drained, Arrayan joins with a group to destroy the castle. The group consists of Artemis, Jarlaxle, Arrayan, Olgerkhan, Mariabronne, Ellery Dragonsbane, Canthan, Athrogate, and Pratcus, as well as a few others. The group battles gargoyles, golems, mummies, and animated skeletons in an attempt to keep the heart of the castle, the tome. The group go to find the true "king" of the castle as Herminicle was the towers "king", know that killing the king will halt the continuing creation of the castle but preserving it as well. They go down through tunnels until reaching the dracolich, Urshula. They battle the dracolich ferociously with Jarlaxle bringing dead humans back to life, with a human skull artifact recovered from Herminicle's tower, to fight against Urshula and Artemis dealing the final blow. The surviving companions return to the near towns to many cheers and many questions.

Reference
Der Hexenkönig