Caladbolg takes form of rather large sword with wide blade. It has jet-black hilt and guard with skull-ornament, while blade itself has cold-blue glow. Blade also has text written on it, written on unknown language.
Caladbolg and Armor of Underworld were found by Paragon from cave, few years after Holy War ended.
Caladbolg seems have ability to increase reach and power of Paragon's Desecration, as well as his destructive power.