48 blazons = 8 sets x 6 elemental types (Light/Shadow/Wind/Fire/Ocean/Earth). Equip once a training facility (stable / archer camp / barracks / workshop) reaches Lv8; up to 6 slots per facility (all 6 at facility Lv29). Sets by troop type: Ground=Justice/Sacrifice, Ranged=Valor/Compassion, Mounted=Honor/Soul, Siege=Honesty/Humility. Each troop type can equip 2 blazons each of Attack, Defense, and HP. Two buff layers: each blazon's own (random) buff plus set buffs that activate at 2/6, 4/6, 6/6 pieces of one set. Blazons start with 2 buffs at Lv1, gain a 3rd at Lv10 and a 4th at Lv15; max level 20. The page states you can reach 'nearly 100%' attack/defense/HP buffs at Lv15. Upgrade by feeding other blazons for EXP: Lv1->10 needs 119 Lv1 pieces, Lv1->15 needs 349, Lv1->20 needs 874 (Lv2+ blazons return 80% EXP as material). Blazons are among the biggest F2P combat levers; farm via monster kills and events. Prioritize your main troop type.
Original research source: Evony Guide Wiki
