I thought up few
1. Return the upgraded armor back to the legendary heroes<uller,vili,himingleva> for rewards. Put the armor in the grave lol
2. Btw...uller,vili and himingleva died right?
How about this quest. Take the mythic armor back to their grave and revive them.
Fight the final boss together with the heroes (lol)
3. Upgrade it again.
Find special loot and essence from the mobs and bosses to upgrade and gain full potential from the mythic set
4. Split the mythic items for a chance and better loot.