Defense/Resistance Solo (Japanese: 守備魔防の孤軍Defense/Resistance Lone Force) is a three-tiered passive type A skill which debuted in Fire Emblem Heroes; the individual tiers of the skill are known as Def/Res Solo 1, Def/Res Solo 2, and Def/Res Solo 3 in order from lowest to highest. Units with a Def/Res Solo skill boost their Defense and Resistance during combat provided they do not have an adjacent ally; the size of the Defense and Resistance boosts are affected by the skill's tier.