A soldier of fortune and human/demon hybrid sent by The Triad to kill the Halliwell sisters, Belthazor is the demon half of Cole Turner. When in demon form, Belthazor is extremely large and muscular, with red skin covered in black tribal markings. Though able to change form at will, he has difficulty retaining his human form if injured.
Belthazor possesses great strength, the ability to cast deadly energy balls which he can also charge up, making them bigger and deadlier, adjusting, and the power to shimmer. He is able to detect the presence of a Whitelighter by touch, and has psychic senses capable of identifying human murderers and tracking shimmers through planes. For a time Belthazor is also gifted by The Triad with, pyrokinesis, telekinesis and the ability to remotely teleport objects, but these powers are removed when he betrays The Triad for the love of Phoebe Halliwell, killing them.
Belthazor's demonic abilities are tied to his inherent evil nature and by turning to good and loving Phoebe he weakens them. His strength and shimmering are unaffected, as is his power to cast energy balls, but his adjusting ability suffered greatly, at times leaving him completely open to freezing by molecular immobilization. Considered one of the deadliest demons, until turning to good, Belthazor murdered hundreds of innocents and witches, without conscience or remorse, earning infamy enough to gain an entry in the Book of Shadows and membership of the demonic Brotherhood of the Thorn for over a hundred years and being known through out the entire Underworld as one of The Source's top assassins. He bested extremely powerful adversaries, both demonic and virtuous, but his final fate comes at the hands of a human woman whose fiancé he had murdered. She strikes him with Phoebe's power-stripping potion, completely eradicating the demonic Belthazor and leaving only a wholly human Cole Turner.
Belthazor makes a return when Cole, imbued with Avatar powers, reverses time to try and prevent Phoebe and Piper from meeting and saving Paige and thus prevent the Power of Three from being reconstituted. Once Cole reverses time, he reverts from all-powerful demon/Avatar to Belthazor. Much to Cole's dismay, Paige, who sneezed and orbed in place, survives the time change by, as mentioned earlier, orbing out at the time of the change and reconstitutes the Power of Three and Phoebe is able to vanquish Belthazor/Cole forever. The Book of Shadows says there is no way to defeat belthazor only a way to vanquish him which requires some of his flesh.