Who was the commander of the Aramean army who had leprosy?

Answer: Naaman

Naaman was commander of the army of the king of Aram and had leprosy.

“Now Naaman, the commander of the army of the king of Aram, was a great man in his master’s sight and highly regarded, for through him the LORD had given victory to Aram. And he was a mighty man of valor, but he was a leper.”— 2 Kings 5:1 (BSB)