An inverse of Djinn, Dao is the higher level Earth Elemental. As such most of its attacks are Earth-related, such as Vulcan Lance, a single target Earth attack, and Gaea Strike Lv. 3, a multiple target attack.
At this point of the game, the player would have access to Air gemstones such as Djinn Amber and Sylphid Topaz, equip them to Blunt-type weapons. Use Air-type attacks and magic (such as Luft Fusion and Thunderburst) if possible.