Mother

Mother (母と子 Haha to ko, lit  Mother and Child in the Japanese version) is Chapter 5 of Fire Emblem Fates.

Strategy
In this chapter, there are not a lot of enemies to fight. However, you will be notified by Azura to avoid the Wyrmslayer-wielding Mercenaries as their swords can cut through dragon scales. The Avatar will already be in an enraged form with massive stats but still retains the same amount of health, so be careful and avoid running into the Wyrmslayer mercenaries.

The boss does not move but will be fighting with Ryoma, who may help remove some of his health. Ryoma may actually be defeated if the enemy he is fighting gets lucky. However this has no bearing on the Avatar or their forces, as he will simply retreat from the map upon defeat. After all the other enemies have been cleared, attack the mysterious stranger; but only with your Avatar, because the stranger will kill anyone else who tries to attack him due to his high stats. Once the stranger is defeated the map will complete.

Reinforcements

 * At the start of turn 6 on hard difficulty, two Dark Mage's will enter the map from the two lower corners.

Trivia

 * This particular chapter is unique in the fact that the Avatar does not emote an audio file during a critical strike, the Avatar is healed or levels up. This is most likely due to story reasons - they are 'mentally incapacitated' and are no more than a raging monster. Their facial emote is seen on the screen during a critical strike, but no audio file is played.