Notched Fin

Notched Fin is a killer whale (Hunters, as the Seal Clan calls them), with a reputation for dangerousness. Tenris once killed his calves, and cut a notch in his fin, thus giving him the name Notched Fin. Other kinds of whales than killer whales can be killed under Seal Clan law, but not Hunters such as Notched Fin. Nordhed Fin ended up eating Tenris in himself after his epic death battle with Torak at the end of Spirit Walker.
Notched Fin's entire plot use was copied by James Cameron in his film Avatar 2: The Way of Water (2022.), for a whale character called Paiakan. See Ways Avatar copied Wolf Brother
P.S. On a whale watching trip I once found out that killer whales/orcas/The Hunters are, in reality, really big-ass dolphins.