Mamluke Mail is one of stronger armors in the game, coming in just after Brigandine.
Mamluke Mail is obtainable by winning a battle where the enemy has Sarranid Mamluke units or from Armor Merchants. The chances of the Mamluke Mail appearing in your loot box is very little, meaning you would have to kill a large number of Sarranid Mamlukes for a good chance of getting some.
Sultan Hakim is one notable wearer of Mamluke Mail. Surprisingly, most Emirs prefer the weaker cavalry robes and shirts over mail than the mail used by their highest tier troops.