This page of our AC Valhalla Dawn of Ragnarok guide shows the locations of all Heroic Sagas appearing in Eitri region.
Gaefuleysi and the Bear
Location: northern part of the city.
To get to the saga you must destroy the blocked wall. The Incendiary Powder Trap ability will work best for this purpose. . Once inside, you will immediately see the saga lying on the wooden countertop.
Gaefuleysi and the Spikey Giant
Location: western part of the city.
This saga is located in a small room, just behind a wooden shelf. However you need to pick up a small wooden chest first in order to move the shelf. Move the shelf and pick up the saga.