High Resistance: The ability to be highly resistant to physical and magical harm and survive otherwise lethal attacks. He was one of the few demons who couldn't be vanquished by his own energy balls and was able to survive Piper's power of Molecular Combustion even in his human form.
Immortality: The ability to possess an infinite lifespan and an arrested aging process.
Through spell, potion, power stealing, etc.
Illusion Casting: The ability to cast illusions. Cole mentioned having learned a trick from the Demon of Illusion and appeared in Phoebe's favorite movie to let her know he was back.
The design for Belthazor was based on the character of Darth Maul in Star Wars: Episode I - The Phantom Menace, which came out the year prior to the premier of Season 3.
The Book of Shadows contains a potion specifically to vanquish Belthazor. However, this contradicts his entry, which states there is no known way to vanquish him. However, since the book is passed down through generations, the potion could have been added later.
Belthazor has the most pages in the Book of Shadows dedicated to him, having a total of four. The Cole Turner page was written by Phoebe, and his main page was written by an unknown ancestor (certainly born before Penny, who created the vanquishing potion).
The demonic form of Alastor the main antagonist of the first season of the reboot resembles Belthazor: they are both bald and possess red skin and sharp fangs instead of normal teeth. Also like Cole/Belthazor, his human form appeared before his demon form.
Appearances
Belthazor has appeared in a total of 10 episodes and 2 comic issues throughout the course of the series.