Below is a walkthrough of The Hunt for Oswald main story event in Rune Factory 5.
Client: Livia
Location: Atohl’s End
Objective: Investigate Atohl’s End
As you progress through the story, the headquarters will have you investigate Atohl’s End in search of the missing Oswald. Exit the town and head northwest to the Kelve Volcanic Region. You’ll can find Atohl’s End on the west side in the southern jungle region.
Atohl’s End 1F
Work your way through the level. You’ll want to keep heading south. Eventually you’ll end up in a courtyard like area surrounded by a couple of tall buildings with a switch. Activate the switch then fight off the enemies that ambush you. Head north one area then follow the path west (this is where the gate you just unlocked will be). In that area, there will be a purple switch you can press. This will open up the way leading to the next floor.
Atohl’s End 2F
In this second area, follow the path heading southwest. In the most southwest room, you’ll find a blue switch you can flip. This will open a gate in the next northern area leading to a treasure chest. Return to the most southwestern square then head east to reach the next floor.
Atohl’s End: Manor
Head to the center of the floor to trigger a dialog event that will lead to a fight with the Dragon Mummy. For this fight, stay behind the dragon to dodge most of its attacks. Also watch out for it to fly up in the area where it can then shoot down multiple darks orbs that deal damage. After you win, a dialog event triggers leading to the end of the event.