While Sitting Bull was the leader of the Hunkpapa Lakota Souix war chief, he did not lead the battle against General Custer.
Crazy Horse did.
George Armstrong Custer was arguably one of the worst men ever to wear the uniform of an American Army officer. He got his head handed to him at the Battle of the Bighorn. And by every objective military standard he deserved to. It’s just a shame the men of the 7th. Cav. had to pay the price as well.