The Dying Earth.

The setting is in an age millions of years into the future of Earth, decades before the Sun goes Red Dwarf to wipe us all out. Humanity is almost extinct, and in an age where science and sorcery are interchangeable, powerful wizards try to recreate people using alchemy and chemical cloning vats. Most of their experiments create short-lived monsters. After one experiment fails spectacularly, a leading mage summons aid from another, for which he has to perform various near impossible magical tasks. This other magus has already failed to create a perfect woman, leaving his creation free to wander the World, though she is incapable of seeing or understanding what is beautiful. She tries to destroy every living thing, flowers and wizards alike. Together, the magicians, one of who is never seen by the other, create a twin of the hate-filled woman, and she is perfectly formed. She is even able to subdue her sister-clone's passion for destruction. T'sais, the woman filled with hate, embarks on a quest to find love and beauty in he dying World, finding both love and hate on her quest. In another thread, a wayfarer, who rashly tries to use it to gain a woman's love, finds a powerful amulet carelessly discarded by one of the magicians. He finds himself pursed relentlessly by the unstoppable and terrifying, if aptly named Chun The Unavoidable. Two other characters embark on a quest to find a library that holds the sum of all human knowledge, a place guarded and threatened by demonic ghosts. They find themselves assigned to protect it until the end of the World, which they know to be soon, but they value the work well enough to standby their duty.