Wings of Gold

Beastmaster Artifact Quest Talk to Brutus in Upper Jeuno and then head to the 10th floor of Upper Delkfutt Tower.

If you still have the Delkfutt Key from rank 4, you can take a shortcut up from Lower Delkfutt Tower. When you enter Lower Delkfutt Tower, take a left at the first intersection and follow the right side of the wall past the stairwell and into a corridor. There will be a cement door on the right, trade your key to it and it will allow you to enter (you do not lose the key). Go through the corridor until you enter a large room, take the first corridor on the left.

To the right of a long stairwell is the ??? at the bottom which will automatically transfer you to the elevator on the 10th floor of Upper Delkfutt Tower.

Kill Gigas on the 10th floor to get a Delkfutt Chest Key.

The chest spawns on the 8th, 9th and 10th floors.

Open the chest to get your axe.