The Helmet - $1 from Dollar Tree - Spray painted silver, hand painted the geometric shapes, hot glue a few camera lenses, and attached an elastic strap to keep it in place. Sealed with clearcoat.
The Chestplate - $1 from Dollar Tree - Primed, spray painted, and then hand painted the shapes. Sealed with clearcoat.
The Backplate - Double corrugated cardboard sandwiched between 2 pieces of cereal box carboard. Primed, painted, and sealed with clearcoat. The chestplate and backplate are attached to each other using velcro.
Shinguards, Bracers, and Pauldrons - Double Corrugated cardboard that was dampened and shaped. Once dry I wrapped them in packing tape for durability, then sandwiched that between pieces of cereal box cardboard. Primed, painted, and sealed with clearcoat.
The Shield - A piece of double corrugated cardboard cut into a shield shape. The shield shape was also cut out of cereal box cardboard but 2 inches larger. The cereal box cardboard was hot glued to the double corrugated shield shape. The excess cereal box was wrapped around and hot glued down. A handle made of cardboard was added. Then I primed and painted a base layer before hand painting the heraldry. Finally, it was all sealed with clearcoat.
The Sword and Axe - Both were purchased at the Dollar Tree for $1 a piece. They were disassembled, painted, sealed, and reassembled.
Bonus - I used the same techniques to make a medieval Batman style costume for my son just because.