Question: What was the name of the person that was interviewed and later written about by John G. Neihardt?

Context:
CCGS John G. Diefenbaker
CCGS "John G. Diefenbaker" is the name for a Canadian Coast Guard icebreaker that is expected to join the fleet in 2021–2022.
 She was initially expected to be in service by 2017.
 Her namesake, John G. Diefenbaker, was Canada's 13th prime minister.
 It was Diefenbaker's government that founded the Canadian Coast Guard in 1962.
A Ballad of the West
A Ballad of the West is Bobby Bridger's a three-part story told in Homeric verse and song about the Mountain Men, William F. "Buffalo Bill" Cody, and the Lakota Sioux people inspired by John G. Neihardt's "A Cycle of the West".
Stark's War
Stark's War is the name of a series of military science fiction novels written by John G. Hemry and first published by Ace Books between 2000 and 2002.
 The books are now being sold with updated cover art highlighting John G. Hemry's nom de plume of Jack Campbell.
 The series covers the invasion of the Moon by the military forces of Earth in a conqueror's role for the resources of the Moon, as the resources of Earth (or The World, as the citizens of the Moon refer to it) are not sufficient to sustain the American economy.
 Following a disastrous initial invasion, Sergeant Stark, the titular hero of the series, seizes control of the American military forces on the Moon.
Black Elk Speaks
Black Elk Speaks is a 1932 book by John G. Neihardt, an American poet and writer, who relates the story of Black Elk, an Oglala Lakota medicine man.
 Black Elk spoke in Lakota and Black Elk's son, Ben Black Elk, who was present during the talks, translated his father's words into English.
 Neihardt made notes during these talks which he later used as the basis for his book.
Amber Brown
Amber Brown is a series of realistic fiction novellas for children created and originally written by Paula Danziger; later written by Elizabeth Levy and Bruce Coville.
 Early editions are illustrated by Tony Ross and later by Anthony Lewis.
 The original series is narrated in first person by Amber Brown, starting near the end of her third grade year and through the summer after her fourth grade year.
 Danziger's balance of humor and real life tribulations are masterfully balanced to reach readers on a deep level throughout the series.
Cycle of the West
A Cycle of the West is a collection of five epic poems (called ""Songs"") written and published over a nearly thirty-year span by John G. Neihardt.
 As one extended work of literature, the "Cycle" treats historical topics from the American settlement of the Great Plains and the displacement of the Native American cultures there.
Amityville: The Final Chapter
Amityville: The Final Chapter is the third installment of the "Amityville" book series written by John G. Jones.
 Most of the book is believed to be fiction unrelated to the actual claims of the Lutz family.
 John G. Jones is A New York Times/worldwide bestselling author/screenwriter/film & TV producer and musician.Amityville : The Final Chapter was supposedly the final book in the series.
 However after the success of this book an entirely fictional Amityville sequel was created titled Amityville: The Evil Escapes.
Hilda Neihardt
Hilda Neihardt (1916–2004) was one of her father John G. Neihardt's "comrades in adventure," and at the age of 15 accompanied him as "official observer" to meetings with Black Elk, the Lakota holy man whose life stories were the basis for her father's book, "Black Elk Speaks" and for her own later works.
John G. Neihardt State Historic Site
The John G. Neihardt State Historic Site, also known as the Neihardt Center, is located in Bancroft, Nebraska, United States and features museum exhibits about Nebraska Poet Laureate John Neihardt.
John Metras
John G. Metras {'1': ", '2': ", '3': ", '4': "} (born c. 1941) was a Canadian football player who played for the Hamilton Tiger-Cats.
 He won the Grey Cup with them in 1965.
 He previously played football at the University of Western Ontario, where his father Johnny Metras coached.
 John G. Metras graduated from Western Ontario in 1964 with a LL.B.
 degree and was called to the bar in 1966.
 His father was later inducted into the Canadian Football Hall of Fame in 1980 as a builder.
 John Metras, Jr. was inducted into the Western Ontario Wall of Champions in 2013.
 He currently works as a lawyer.

Answer: Black Elk