Orca is a character from The Legend of Zelda: The Wind Waker. He is a relatively old man who lives on Outset Island, a peaceful place where Link also resides. He is the only man on the island with any knowledge of swordplay or battle. He is the brother of Sturgeon and the great-uncle of Sue-Belle.
In his youth, Orca, along with his older brother Sturgeon, set out on a quest to find ten Knight's Crests. Both of them aspired to be great swordsmen, and their quest took many years of hard toil and honing their skills of the blade. Both fought against beasts and challenged each other to become stronger. Some time at the end of their journey, Orca received such injuries that he was unable to become a swordsman. After their journey, they built a house on Outset Island in which Sturgeon lived in the top portion and Orca lived on the bottom. While Orca may no longer use a sword, he does train with a spear.
At the beginning of Link's journey, Orca teaches Link to use a sword. After Tetra is dropped into the forest, Orca teaches Link more techniques such as the Spin Attack and parrying before giving him the Hero's Sword to help on his quest.
If Link brings him ten Knight's Crests, he will teach him the Hurricane Spin.
Later on in Link's adventure he can play the Training Game with Orca. It involves Link trying to hit Orca as many times as possible without getting hit three times. However, a successful parry attack against Orca is counted as two hits instead of one. If Link hits Orca 100 times before getting hit three times, Link receives 50 Rupees, and will be addressed as a "knight", rather than a "page". If Link hits Orca 300 times, Link receives 100 Rupees and is called a "swordsman". If Link hits Orca 500 times, Link receives a Piece of Heart. If Link hits Orca 1,000 times, Link will receive 200 Rupees, and Orca will say that Link has surpassed him and call him a "master" from that point on. He also breaks the fourth wall at this point by curiously asking if Link's left index finger is sore, presumably due to the prolonged L-targeting during the battle.
Many characters in The Wind Waker carry a name of an aquatic nature. Orca is another name for the Killer Whale.