III: The Changing Tide (参：揺れる面影, San: Yureru Omokage lit. 3: Swaying Vestiges in the Japanese version) is Xenologue 17 of Fire Emblem Fates.
Subjective: The following part of this article is subjective to the editor's writing. Therefore, it may not work for everyone.
In this Xenologue, the player uses the remaining Hoshidan children. Like the rest of the Heirs of Fate maps, if the children's health falls to 0, they will simply retreat from the map. Shiro, Asugi, and Caeldori carry an exact replica of the items/skills they had in the last Xenologue. Midori and Rhajat, however, have a slight change in their inventories. Midori's Dragon Herbs get switched out for an Azura's Salve and Rhajat gains a Horse Spirit.
Be warned that none of the children are healers and therefore the player cannot use healing staves, as well as that healing items are limited to one stack of Vulneraries (held by Caeldori), one Azura Salve (Midori), one stack of Concoctions, and one Elixir, the latter two being drops from enemies around the map, though Asugi and Caeldori can recover small amounts of HP gradually through their skills, and Midori can recover more HP when using the limited number of healing items provided.
The units that make up the map are mostly Faceless and the six Nohr children from Heirs of Fate 2. Various reinforcements will appear at some of the tombstones in the marshes. Three Stoneborn position themselves at some of the marshes, and possess the Strength Seal skill. This can seriously cripple everyone but Rhajat, who takes a lot of damage from the Stoneborn anyways, and Flame Shuriken Asugi, which is considerably weaker than Steel Shuriken Asugi anyways.
Players can either rush the two bosses, although this only recommended if the player is not interested in the Strengthtaker reward at the end of the chapter, or fend off enemy waves before attacking. Pair up Shiro with either Asugi or Caeldori, although it is recommended to have Asugi pair up with him for the extra point of movement for Shiro, as either one provides the same speed boost, which is vital to doubling enemies in this chapter. Alternatively, Midori provides a small boost to Defense and lets Shiro takes more hits, which may be desired more when dealing with the Faceless who have Heartseeker.
Forrest can be easily defeated with Shiro in two turns, as he will be unable to kill him in a round of combat due to his high health, but if Shiro is weakened then Forrest is more likely to kill. Shiro should easily be able to avoid most of the enemy attacks, and his Vantage should allow him to kill them if he falls below half health. Fortunately, Forrest does not move so he can be taken care of last. After enough turns go by, some of the enemy units will move to surround Forrest (most likely to be Ophelia, Nina, and the nearby Maid).
Kana, Dwyer and Sophie however, will move after enough times have passed. Caeldori can easily kill off Kana with her Swordcatcher, though she isn't able to take him down in one hit, so the player may want to weaken Kana beforehand using Shiro or Asugi. Sophie can be defeated with Rhajat or Flame Shuriken Asugi. If Dwyer is not defeated, he will move to support Forrest.
- At the end of turn 1, a Fighter and two Faceless will appear from the southwestern pool.
- At the end of turn 3, a Maid, a Lancer and a Knight (both equipped with a ranged lance) will appear in the southeastern pool.
- At the end of turn 6, a Wyvern Rider and Archer appear in a Guard Stance, in addition to a Sky Knight in the northeastern pool.
- At the end of turn 8, a group of two Faceless in a Guard Stance and two other Faceless will appear in the central spot.
- Strengthtaker (all player units survived)