A clan origin
This story explains the origin of the killer whale and why one Tlingit clan uses it as a crest. It follows the short version John R. Swanton published in 1909 as 'Origin of the Killer Whale', and notes where widely retold versions add more.
The failed carvings
Naatsilanéi, of the Tsague'dî, a branch of the DAqL!awe'dî, set out to make killer whales. He carved them first from red cedar, but when he put them in the water they only floated. He tried hemlock, and then other woods, and each time the carvings lay on the surface like driftwood.
Yellow cedar
Then he carved them from yellow cedar. When he put these in the water, they came alive and swam. He made them in several kinds, marking one with white paint so that it became the white-mouthed killer whale, and he named the long, slender red one that swims at the front 'killer-whale-spear'.
The instruction
He told the whales that when they went up to the heads of the bays they were to hunt for seal, halibut, and everything else under the sea, but that they were never to hurt a human being. Because the Tsague'dî are a branch of the DAqL!awe'dî, Swanton records, the DAqL!awe'dî alone use the killer whale as their emblem.
Other tellings
Many later tellings frame the carving with a story of betrayal: jealous brothers-in-law abandon Naatsilanéi on a distant sea rock, the sea lions rescue him, and his first command to the new whales is to overturn the brothers-in-law's canoe, before he forbids them ever to harm people again. Those episodes come from those other tellings, not from Swanton's text.