Cassim is the firelord of the Fire Nation.
King Of Thieves

Cassim, the reigning firelord

About him

Firelord Cassim is the Firelord in the Fire Nation, the son of the Late Firelord Sharaman and Firelady Talia, the brother of Jafar, the husband of Esmeralda, the father of Avatar Aladdin and the father-in-law of Jasmine. He is also a master firebender, as most firelords are considered to be.