After proving yourself worthy to the Wind Tribe, you ascend the Eternal Stairway in the hope of reaching Hoshido.
Escape With All Units
To successfully complete this battle, all of your units need to reach the red tiles in the north of the map and choose the Escape option while standing on a red tile. However, even if any of your units die, you will still win the battle if at least one of your units survives to escape.
The map is full of Faceless, and some Stoneborn. The Stoneborn cannot move, but they can throw rocks up to five tiles away.
There are Dragon Veins throughout this map that will freeze all enemy units for one turn. This is key to winning the battle, because more Faceless will appear in the south and north of the map throughout the battle, and they could easily surround and overwhelm you. Unfortunately, the reinforcements give no EXP because of their Void Curse skill.
Camilla can be very helpful in this battle, because she can freely fly to the nearest Dragon Veins to freeze the enemies for you. However, she will likely have to enter the attack range of a Stoneborn, so be sure to keep healing her so she won't be killed by the rocks that they throw.
Equipping Elise with a Physic staff will allow her to heal from a distance and avoid enemy ranges.
Keep an eye out for debris. There are piles of debris throughout the map, some of which block one side of the stairway, forcing you to take a winding path northward.
If you bring a lot of flying and mounted units, you can pair them up with walking units to attempt to quickly ride north with everybody. Keeping everybody paired up will prevent your own units from becoming obstacles to your escape.
All of the enemies here have low Resistance, so attack with Magic when possible. These enemies are all in the monster category, so weapons like the Blessed Bow will be strong against them.