The Guardian's ward is an item dropped by monsters in Daemonheim. It requires a Defence level of 94 to equip. It surpasses the stats of the protector's ward, and a majority of the standard Dungeoneering shields - only the Tier 11 shields provides higher defensive bonuses. It is only dropped by spiritual guardians.
When its appearance is compared to the protector's ward (guardian's ward's weaker equivalent), it seems very similar. The only differences are the more organic colour scheme with elaborate design, and the open eye in the centre, as opposed to what appears to be a "sewn shut" eye in the centre of the protector's ward.
Prior to the Evolution of Combat update, the guardian ward specialised in magic defence, being overall comparable to the gorgonite kiteshield. Since then the ward has had a major improvement, now being the second best magic-class shield available in Daemonheim (after Celestial shield).