Question: Which author was also a soldier, James M. Cain or Alain-Fournier?

Context articles: William H. Keith Jr.
Patrick Cain
The Unknown Soldier (novel)
Alain-Fournier
Susan Cain
William J. Coughlin
James M. Cain
Jim Cain (defensive end)
Artemus James
Soldier Boy (short story)

William H. Keith (born August 8, 1950) is an American author, who writes also under several pen names, such as Ian Douglas, Robert Cain and H. Jay Riker.
Patrick James Cain Sr. (April 1, 1962 – March 14, 2016) was an American football offensive lineman who played one season with the Detroit Lions of the National Football League.
 He first enrolled at California State Polytechnic University, Pomona before transferring to Wichita State University and attended Pomona High School in Arvada, Colorado.
 Cain was also a member of the Denver Dynamite and Washington Commandos of the Arena Football League.
 He was a member of the Denver Dynamite team that won ArenaBowl I.
 He died of lung cancer in 2016.
The Unknown Soldier (Tuntematon sotilas) is author Väinö Linna's first major novel and his other major work besides "Under the North Star".
 Published in 1954, it is a story about the Continuation War between Finland and the Soviet Union as told from the viewpoint of ordinary Finnish soldiers.
 Gritty and realistic, it was partly intended to shatter the myth of the noble, obedient Finnish soldier.
 In Linna's own words, he wished to give the Finnish soldier a brain, an organ lacking in earlier depictions — this was a barb directed at Johan Runeberg's "The Tales of Ensign Stål", which admiringly portrays Finnish soldiers with big hearts and little independent intellect.
 The novel is based on Linna's own experiences, but is more or less fictional.
 In its structure and style, it may be compared to the war novels of James Jones.
Alain-Fournier (] ) was the pseudonym of Henri-Alban Fournier (3 October 1886 – 22 September 1914), a French author and soldier.
 He was the author of a single novel, "Le Grand Meaulnes" (1913), which has been twice filmed and is considered a classic of French literature.
Susan Horowitz Cain (born 1968) is an American writer and lecturer, and author of the 2012 non-fiction book "," which argues that modern Western culture misunderstands and undervalues the traits and capabilities of introverted people.
 In 2015, Cain co-founded Quiet Revolution, a mission-based company with initiatives in the areas of children (parenting and education), lifestyle, and the workplace.
 Cain's 2016 follow-on book, "," focused on introverted children and teens, the book also being directed to their educators and parents.
William Jeremiah Coughlin (1929 - 1992) is the popular author behind such novels as "The Twelve Apostles, Her Father's Daughter, Her Honor, In The Presence Of Enemies," and "Shadow of a Doubt" (1991).
 He also wrote "Cain's Chinese Adventure" and "The Mark of Cain" under the pseudonym Sean A. Key."
James Mallahan Cain (July 1, 1892 – October 27, 1977) was an American author and journalist.
 Cain vehemently opposed labeling, but he is usually associated with the hardboiled school of American crime fiction and is seen as one of the creators of the "roman noir".
 Several of his crime novels inspired successful movies.
James Edgar Cain, Jr. (October 1, 1927 – October 5, 2001) was an American football defensive end who played five seasons in the National Football League with the Chicago Cardinals and Detroit Lions.
 He was drafted by the Chicago Cardinals in the seventh round of the 1949 NFL Draft.
 He played college football at the University of Alabama and attended Eudora High School in Eudora, Arkansas.
 Cain was also a member of the Calgary Stampeders Canadian Football League.
Artemus James is an American singer/songwriter, and multi-instrumentalist.
 He is the lead vocalist/songwriter for the band Year of the Bear.
 He is also known as Cain from the duo formed in early 2009 with Annabelle LaFoy, Cain & Annabelle.
"Soldier Boy" (also known as "X Minus One #71: 56-10-17 Soldier Boy") is a 1953 science fiction short story by American author Michael Shaara, about a soldier who, when sent on a routine patrol to a colonized world, saves the planet from an alien and its robot attack devices.
 Despite an ingrained contempt for the military that arose as part of conditioning to avoid war, the human colonists gradually assist the soldier when strange occurrences suggest they are not alone on the planet and may be, like several other colony planets, under threat of extermination by outside forces.
 It was originally published in the July 1953 issue of "Galaxy Science Fiction".
 It is also the title of a 1982 collection of Shaara's short stories