The Ancient Guardian is an enemy encountered during Desert Treasure II. It has a shield that must be depleted before it can take damage. Ancient Magicks may be used to deplete the shield but the guardian is immune to damage from the spells themselves.
Due to the speed at which the shield recharges, it is recommended to use a weapon with an attack speed of 4 ticks or less. Any missed attack with a weapon that takes 5 ticks or more will result in the shield starting to recharge before the next attack.
The Ancient Guardian has a special attack where it will smash the ground. This will drop boulders from above, and can cause upwards of 25 damage if not avoided. This can be avoided by avoiding the shadows that appear on the ground. One boulder will always be positioned on your current tile.