This mystery can be found in the west of Suthsexe, about 720m northwest of Guildford, AC Valhalla.
What to Do with the Goliath
When you reach the area you’ll find numerous burning straw figures in a field. In the north there’s a Goliath sat on a throne of hay. He won’t attack until you attack first, but he will become aggressive if you loot his treasure chest.
Whatever you choose to do beforehand, you’ll need to kill the Goliath to complete the mystery. This should be an easy task, since he’s gone completely mad and is all alone.