Black Armor is available in Mount&Blade: With Fire & Sword. It can either be crafted from an Armor-Master in a town or fortress or bought from an armor marketplace from towns or fortresses of the Kingdom of Sweden or the Polish Commonwealth.
Black Armor is the strongest armor in the game. Base Black Armor found in the marketplace has ratings of 60 upper body and 32 leg, whereas crafted armor has 58 upper body and 36 leg. Armor found in the marketplace also has the potential for having prefix modifiers which could make the armor much stronger than crafted. Base Black Armor purchased in the marketplace also has the potential of being considerably cheaper than crafted depending on the player's relationship with the town and the party's trade rating.
It is usually paired with an Armet (the strongest head armor in-game). This results in a greatly appealing hero. It costs a hefty 108,000 thalers from an armorer (60000 if the player is lord of the town) and is very heavy, so it's only practical late-game, with plenty of athletic skill.