Demon Lord (Balthazaar) is a paid to play hero which requires you to make a purchase(s).
Gold Attributes:
Hero ATK up by 30%
Barracks training SPD up by 20%
Increase Cavalry ATK by 30%
Army HP up by 25%
Skin Gold Attribute:
Increase Army ATK by 20%
Collecting Shards:
You need to purchase multiple packs to upgrade this hero.
Collecting Skin Shards:
You need to purchase packs to upgrade its skin (Frost Lord).
Note: Balthazaar is a all-round attack hero, favouring Cavalry.
His Drill sergeant ability gives barracks training speed.