Bosk was a sinister Low Level Demon with minimal powers. He rode a magical, flying carpet and shot light darts at his victims as a method of attack.
He had been using his Demonic Forty Thieves to search for the former site of Zanbar. If he found it and wished it back, there would be no stopping him, he would become invincible. Bosk used Jinny's bottle to try to find the city, but the Genie was lost to the Charmed One. Bosk was protected from witches magic using the Eye of Aghbar. Soon he was vanquished by Jinny, who wanted the power that would come with locating Zanbar for herself.
(Book of Shadows text:)