The Vestal (ウェスタ Vesta) is a combat magical class that is introduced in Fire Emblem Echoes: Shadows of Valentia. Said to be priestesses sacrificed to the dark god during ancient times, similar to the Witch class they wield Black and White magic as their primary weapons of choice and have the ability to teleport from one point to another in any given skirmish.
The name Vestal and Vesta may stem from Vesta, the Roman goddess of the hearth.
The generic Vestal portrait looks similar Rinea in her witch form, but with shorter hair and no bangs.
Vestals appear to exhibit odd behavior compared other enemies that are found while the player is exploring dungeons. Such behaviors include: moving at high speed on a clearly definite path (rather than slow, aimless wandering), being only able to spot the player when stopping, and having difficulty chasing the player once alerted. Documented in this video here.
Generic class portrait of a Vestal from Echoes: Shadows of Valentia.