Medieval female fantasy armor breastplate or cuirass,for Roleplay and cosplay Halloween costume armor Female chest plate armor (breastplate/cuirass). ypically made from polished or mirrored steel, sometimes 18 or 20 gauge steel, or other metal alloys. Popular for fantasy events, medieval re-enactments, and various costume events like Halloween or conventions. Description female fantasy armor breastplate or cuirass, a type of body armor often used for cosplay, live-action role-playing (LARP), or re-enactment purposes. This specific piece is a polished steel half-armor that covers the chest and is secured with black leather straps over the shoulders and around the back.