Eternal Stairway (location)

The Eternal Stairway is a location in Fire Emblem Fates.

Birthright
The Eternal Stairway is first visited in Chapter 8, where the Avatar and their allies cross though it to get through the Wind Tribe. The Avatar complains about how long the staircase is and groans when they are notified that they're only halfway through it. Suddenly, Faceless ambush the Hoshidans. The Avatar and Kaze kill the Faceless, only for the magic to drop and reveal them as Wind Tribe members. Iago teleports in, mocks the Avatar, knowing he can plot against them with the Avatar on the Hoshido side and then teleports out to prevent the Wind Tribe from finding out that it was a ruse.

Conquest
The Eternal Stairway is visited in Chapter 21, where the Avatar and the Nohrian siblings cross though it to get to Hoshido, but unknown to them, Iago summons a large horde of Faceless to ambush them at the Eternal Staircase. Unbeknownst to him, Iago has unintentionally helped the Avatar and the Nohrians clear the Eternal Staircase, which was guarded by a group of Hoshidan soldiers to halt the Nohrians' advance. Iago's plan is again foiled as the Nohrian army barely manages to break free of the Faceless horde and Lilith sacrifice herself to save the Avatar from the Faceless. Although disappointed by the fact that his scheme has failed, Iago expresses content through Lilith's death.

Revelation
Like in Birthright and Conquest, the Eternal Stairway is visited in Chapter 9, where the Avatar and their allies cross though it to get through the Wind Tribe. Suddenly, like in Birthright, Faceless ambush the army. The Avatar, Gunter and Kaze kill the Faceless, only for the magic to drop and reveal them as Wind Tribe members. Iago, who was responsible for this, quietly warps out of the scene, pleased with the success of his deceit.

Trivia

 * This is one of only few locations to be visited in all three routes, the other one being Fort Jinya and Sevenfold Sanctuary, however unlike the last two, it is only playable in Conquest, and not in Birthright and Revelation.