The defender's insignia is a reward from Barbarian Assault that can be purchased with 500 defender points if you are a level 5 Defender and have killed the Penance King at least five times. The insignia has a baseline effect at all times that increases your worn armour bonus by 25, doubled to 50 if you're using a shield. When the insignia is charged with an insignia recharge, the bonus increases by a factor of six -- 150 without a shield, or 300 with one. The insignia slowly loses charge while you are in combat, and needs to be recharged once in a while to keep the extra bonus. The insignia will appear in your gravestone on death and will not have lost any charges.