Aegis (Holy Shield in the Japanese version) is a Skill from Fire Emblem: Awakening that halves damage from Bows, Magic, and Dragonstones. The activation is (Skill)%. It is learned by Paladins at Level 15. It does not apply for Dual Attacks.
Aegis (from the Greek Αιγίς), as stated in the Iliad, is the shield or buckler, or breastplate, of Athena and Zeus, famously bearing Medusa's head, which, according to Homer, was fashioned by Hephaestus.