那是大蛇丸留下的“礼物”。

In the Naruto universe, a cursed seal (also known as a "jūjin") is a type of dark magic that allows a user to seal and control a powerful entity, often a demon or a spirit, within themselves. This entity can grant the user immense power, but at a terrible cost, slowly consuming their soul and eventually taking control of their body.

“力量……”

For one terrible minute, Sasuke was happy.

The transformation was not heroic. It was wrong . Skin grayed to ash. Hair darkened to ink. From his back, membranous wings of pure chakra tore through his shirt—not to fly, but to loom . He moved like a puppet whose strings had been cut, yet faster than any living thing. Against the sound ninja, he didn’t fight. He unmade . Each strike was precise, cruel, and utterly without hesitation.