Fire Emblem Heroes Guide: 20 Crucial Tips & Tricks You Need To Know
11. Determine Whether To Attack Or Defend
Depending on the situation, it may not always be a good idea to attack enemy forces. When you hover over a unit to attack it, you can see the damage dealt - this factors in everything, from Weapon Type bonuses and penalties to any Special or Passive Skills which may become active during combat.
Unless specific skills are modifying the order of attack, the initiating unit will always attack once first, followed by a retaliatory strike from the defender. If either unit has a Speed advantage of five or greater, it will then get its second attack (after both units have hit once). However, as soon as a unit’s HP reaches zero, it cannot attack any further.
This means that, if neither unit can kill the other in one attack, it can sometimes be worth allowing your opponent to initiate the first combat - allowing your unit to retaliate.
Once both Heroes are damaged, you can then attack first on your next turn and defeat the enemy unit, preventing them from striking back. Be mindful of other factors, too, such as bonuses conferred by adjacent units or whether you should heal a unit before or after it attacks an enemy for maximum value.