Buster Kilrain is the only fictional character in Michael Shaara

Michael Shaara

Michael Shaara was an American writer of science fiction, sports fiction, and historical fiction. He was born to Italian immigrant parents in Jersey City, New Jersey, graduated from Rutgers University in 1951, and served as a sergeant in the 82nd Airborne division...

's 1974 novel about the American Civil War

American Civil War

The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

 Battle of Gettysburg

Battle of Gettysburg

The Battle of Gettysburg , was fought July 1–3, 1863, in and around the town of Gettysburg, Pennsylvania. The battle with the largest number of casualties in the American Civil War, it is often described as the war's turning point. Union Maj. Gen. George Gordon Meade's Army of the Potomac...

, The Killer Angels

The Killer Angels

The Killer Angels is a historical novel by Michael Shaara that was awarded the Pulitzer Prize for Fiction in 1975. The book tells the story of four days of the Battle of Gettysburg in the American Civil War: June 30, 1863, as the troops of both the Union and the Confederacy move into battle around...

. His surname is a portmanteau of the title "The Killer Angels". In the 1993 movie based on the book, Gettysburg, and the prequel Gods and Generals

Gods and Generals (film)

Gods and Generals is a 2003 American film based on the novel Gods and Generals by Jeffrey Shaara. It depicts events that take place prior to those shown in the 1993 film Gettysburg, which was based on The Killer Angels, a novel by Shaara's father, Michael...

, he was played by actor Kevin Conway.

According to the novel Gods and Generals written by Shaara's son Jeff

Jeffrey Shaara

Jeffrey M. "Jeff" Shaara is an American novelist, the son of Pulitzer Prize winner Michael Shaara.Jeffrey Shaara was born in New Brunswick, New Jersey and grew up in Tallahassee, Florida...

, Kilrain was born in 1812 in Belfast

Belfast

Belfast is the capital of and largest city in Northern Ireland. By population, it is the 14th biggest city in the United Kingdom and second biggest on the island of Ireland . It is the seat of the devolved government and legislative Northern Ireland Assembly...

. He was originally a sergeant

Sergeant

Sergeant is a rank used in some form by most militaries, police forces, and other uniformed organizations around the world. Its origins are the Latin serviens, "one who serves", through the French term Sergent....

 before being demoted to private

Private (rank)

A Private is a soldier of the lowest military rank .In modern military parlance, 'Private' is shortened to 'Pte' in the United Kingdom and other Commonwealth countries and to 'Pvt.' in the United States.Notably both Sir Fitzroy MacLean and Enoch Powell are examples of, rare, rapid career...

 for assaulting a superior officer while drunk. According to The Killer Angels and Gettysburg, he died on the morning of July 3, 1863, after being wounded twice while helping to defend Little Round Top

Little Round Top

Little Round Top is the smaller of two rocky hills south of Gettysburg, Pennsylvania. It was the site of an unsuccessful assault by Confederate troops against the Union left flank on July 2, 1863, the second day of the Battle of Gettysburg....

 the day before.

The novel's usage of the name "Buster" is an anachronism

Anachronism

An anachronism—from the Greek ανά and χρόνος — is an inconsistency in some chronological arrangement, especially a chronological misplacing of persons, events, objects, or customs in regard to each other...

. Although the word is an Americanism that dates to at least the 1830s, it is not known to have been used as a first name at the time of the American Civil War. The popularization of the word as a first name or nickname did not come about until the early twentieth century because of its usage by Buster Keaton

Buster Keaton

Joseph Frank "Buster" Keaton was an American comic actor, filmmaker, producer and writer. He was best known for his silent films, in which his trademark was physical comedy with a consistently stoic, deadpan expression, earning him the nickname "The Great Stone Face".Keaton was recognized as the...

.

It is likely that Michael Shaara based the character of Kilrain partly on the 20th Maine

20th Maine Volunteer Infantry Regiment

The 20th Maine Volunteer Infantry Regiment was a combat unit of the United States Army during the American Civil War, most famous for its defense of Little Round Top at the Battle of Gettysburg, July 1863.-Organization:...

's Sergeant George Buck. One day Buck was ill and stayed behind at camp. When a quartermaster ordered him to chop wood, Buck refused and the officer struck him. Colonel Joshua Lawrence Chamberlain was ordered to demote Buck to the rank of private. At Gettysburg, Buck was critically wounded and just before he died, Chamberlain promoted him back to his previous rank of sergeant.

The character of Kilrain also appears as the subject of a song about the Civil War by Steve Earle

Steve Earle

Stephen Fain "Steve" Earle is an American singer-songwriter known for his rock and Texas Country as well as his political views. He is also a producer, author, a political activist, and an actor, and has written and directed a play....

called "Dixieland".