Unfortunately, Aethers cannot be recovered once they are used. As Empires & Puzzles is an online multiplayer game, we cannot revert irreversible in-game actions for specific players on request. Doing so would not be fair for other players.

Although you will not be able to recover the Aethers used, please keep in mind that a Limit Broken Hero is remarkably powerful once fully leveled up. The Hero should still be a valuable asset for you in various future events and quests.