In Joshua 5, Joshua meet a man with a sword near Jericho. Who was the man?

The captain of God's army

And it came to pass, when Joshua was by Jericho, that he lifted up his eyes and looked, and, behold, there stood a man over against him with his sword drawn in his hand: and Joshua went unto him, and said unto him, Art thou for us, or for our adversaries?

And he said, Nay; but as captain of the host of the LORD. Joshua 5:13-14