Nightwolf appears in Mortal Kombat as the one who teaches Liu Kang. He taught his student how to use Animality. He also assisted Liu Kang as the Mortal Kombat universe's protagonist in passing trials to get a chance to fight and defeat Shao Kahn.
He comes from the Lakota-Sioux tribe and calls him Raiden as Haokah. In Mortal Kombat 11 it became known that at the moment his tribe is called Matoka.
Nightwolf travels with his tamed Kiba wolf, who helps him use the shaman's powers. As you might guess, this character also knows how to communicate with wolves and, perhaps, considers them his friends.
Nightwolf probably didn't have these skills from birth. The name "Night Wolf" is a title that is passed from person to person in the Matoka Indian Tribe. It was this title that gave this native American his superpower.
A historian and shaman well in tune with nature. He has allied with Raiden to protect Earthrealm from those who seek to destroy it, conquer it, or even something worse.