@Mr-BoyMan_Dude probably because Orcas kill whales.
Whale Killer became Killer of Whales into Killer Whales. They're also not actually whales but closer to dolphins.
They'll literally drown other whales to eat them. Australian whalers have reported them driving baleen whales into the bay close to whaling boats, in return for the whales tongue and lips. Look up Law of the Tongue.
They also slaughter narwhals, minke whales, dolphins, seals, sea lions, sharks and penguins for food.
They're literally the most successful predator in the ocean.