King Zora Secret
Learn the Secret
The King Zora Secret can be learned after Link obtains the Roc's Feather from the Poison Moth's Lair. It will allow Link to travel farther into the Hero's Cave and meet with the Hero's Cave Zora, originally from Zora Village in Labrynna. He says he was sent by King Zora to find a new domain in Holodrum. The Zora will ask Link to tell his secret and report to King Zora back in Labrynna.
Tell the Secret
Back in Oracle of Ages, Link can visit King Zora during the present day. After telling him the secret, King Zora will reward him by sharpening his sword.
By sharpening Link's Sword, it will upgrade whichever sword he previously has. If Link has the L-1 Wooden Sword, it will upgrade to the L-2 Noble Sword. If Link already had the Noble Sword, it will become the L-3 Master Sword, the most versatile weapon in the game. King Zora will give Link a secret that he can take back to Oracle of Seasons, where he can get his sword sharpened there as well.
Speak to King Zora