Who is Gian Hen Gian from Practical Demonkeeping: A Comedy of Horrors and what is their importance?

Gian Hen Gian is the King of the Djinn, an Arabic-looking, small-statured creature who sends blue swirls flying in the air when he curses. Gian Hen Gian is addicted to salt from his time trapped in a bottle in the ocean, when he drank the salt water that dripped into his prison.