The 2nd book in the Tyrion and Teclis series by William King

Tyrion – Unparalleled swordsman and tactician.
Teclis – Greatest natural sorcerer of the age, his power rivalling that of fabled Caledor.

Together these twins are the greatest high elf heroes to still walk the earth.
Tyrion and Teclis venture into the deadly jungles of Lustria on a desperate hunt for the lost sword of Caledor Dragontamer, the fabled Sunfang. While they search for this ancient artefact, the Witch King Malekith continues his assault on Ulthuan, sending the deadly assassin Urian Poisonblade to kill the Everqueen. And in the Realm of Chaos, the sorceress Morathi makes a pact with another enemy of Tyrion and Teclis – the sinister daemon N’Kari.