What is the name of the ultra-orthodox islamic group that was in power in afghanistan until the united states military intervened in fall of 2001?

The correct answer is Taliban

They were an extremist fundamentalist religious group that ruled Afghanistan until 2001. As of 2001 they are no longer a government body that rules, but rather an insurgency group that opposes any other government. They still exist and adhere to their ideas of practicing Sharia law which was changed a bit to suit their needs.