Chain Attack is a game mechanic introduced in Fire Emblem Engage. Similar to Dual Strikes from the Dual System, Chain Attacks allow multiple units to attack the same target. When a unit targets an enemy, ally units in the Backup Battle Style trigger a Chain Attack if targeted enemy is in their attack range. Multiple characters can join Chain Attacks provided they meet the conditions. The Chain Attackers will attack before the initiating unit; each Chain Attack deals damage equal to 10% of the target's maximum health, bypassing Defense and Resistance, and also has a fixed 80% hit rate.

Certain Skills can also influence Chain Attacks; for example, the phantoms summoned by Emblem Lyn's Call Doubles Engage Skill can join in Chain Attacks with the unit that summoned them regardless of their location on the map, Hero's class skill Brave Assist causes unit's Chain Attacks to hit twice, Emblem Lucina's Dual Strike Sync Skill and her All for One Engage Attack can enable units to participate in Chain Attacks regardless of their Battle Style, while Dual Assist adds a chance of triggering a Chain Attack if target is not in attack range, but can be reached with full movement. Emblem Corrin's Pair Up skill negates damage from Chain Attacks.