Lull Speed/Defense is a Type B passive skill introduced in Fire Emblem Heroes. Exclusive to infantry and cavalry units, the skill inflicts an in-combat penalty on enemies targeting their Speed and Defense, while also nullifying the target's visible stat buffs on those two stats during combat.
Inflicts Spd/Def-X on foe [X = 4 + number of [Bonus] effects active on foe; max 8 ;excluding stat bonuses) and neutralizes foe's bonuses to Spd/Def (from skills like Fortify, Rally, etc.) during combat.