FIGHT: Talk to Master Raven (X:253 Y:250) in Copperhorn Mountain, you will be fighting Master Raven (level 35 non-elemental Blademaster, 18,136 HP).
Upon defeating him, head to Giantwood Forest near the middle Forestry collection area to find Anthony and Johnny next to the Forestry Merchant (X:263 Y:312).
FIGHT: After listening to their conversation, talk to one of them. You will be fighting against the two of them (level 30 non-elemental Blademasters, 5,006 HP) and another blademaster named Marie (level 35 non-elemental Blademaster, 20,350 HP).
Once you have defeated them, pick up the Grand Gold Sword before the plot event ends.
Report back to Master Raven in Copperhorn for your rewards.