The Marcus NPC sells armor and misc items.
LOCATION
Marcus is located in the spawn section of every map (Kings, Elements, and Seasons).
SHOP
Marcus sells three categories of items (Beginner Armor, Armor, and Misc) and has an Upgrade Armor feature, allowing you to upgrade the Protection on your Diamond Armor.
Beginner Armor
Protection 1 Diamond Armor
Armor
Protection 2 Diamond Armor