Defense/Resistance Oath (Japanese: 守備魔防の信義Defense/Resistance Loyalty) is a three-tiered passive type C skill which debuted in Fire Emblem Heroes; the individual tiers of the skill are known as Def/Res Oath 1, Def/Res Oath 2 and Def/Res Oath 3 in order from lowest to highest. Units with a Def/Res Oath skill will, if the user is adjacent to any allies at the start of their phase, receive a boost to the user's Defense and Resistance for the duration of the turn; the Defense and Resistance boosts increase with the skill's tier.