The articles below were provided by Jean Hounshell Peppers.  Please note the first article confuses Cap with his father and the second one indicated that Cap was dying in 1906 of a gunshot wound inflicted by his brother, Elias.  That article also indicates Cap instead of Devil Anse was the head of the clan, which was not accurate.
Cap Hatfield Dies: Famed as Feudist
Special to the New York Times Associated Press Photo
New York Times 1857; August 23, 1930 pg. 8

“Cap” Hatfield Dies; Famed as Feudist
Was Leader in Kentucky – West Virginia Clan Fights That Lasted Half Century
More Than 100 Lives Lost
Central Figure in Mountain Wars
Spent Last Years In Peace – Succumbs in Baltimore
Special to the New York Times

Baltimore, MD, Aug. 22 – “Cap” William Anderson Hatfield of Loan, W. Va., who with others of the Hatfield family figured in the notorious Hatfield-McCoy mountaineers’ feud which raged in Southwestern West Virginia for half a century, died today at the age of 68 at the Johns Hopkins Hospital from a brain ailment.

Accompanied by his wife, a son and a daughter, the mountaineer arrived in Baltimore Sunday and was taken to the hospital in an ambulance, for he had been ill for two months at home.

In more recent years the younger members of the family came out of the mountains, forgot their interfamily troubles and attended Southern schools.

“Cap Hatfield was called the most dangerous of his clan.”  Born in 1862, the year after the famous McCoy-Hatfield vendetta commenced, he was the eldest of the thirteen children of Anderson (Devil Anse) Hatfield, chief of the clan and its leader throughout the forty-eight years of the feud.  More than 100 men, women and children of the two families were slain in the battles, which raged in Logan and Mingo Counties, West Virginia, and Pike County, Kentucky.

It was said in those days that whenever a McCoy head showed out of a window a Hatfield gun would bark; whenever a Hatfield gazed from his home at the surrounding hill country a McCoy gun would bark.  Before the Civil War the two families, large landowners – the McCoys in Kentucky and the Hatfields in West Virginia – were friendly.  They had been brought together by business and intermarriage.  The sons of both families joined the home guards and took part in raids into the bordering States.  Thus their relations became strained.

Trouble Began Over Stolen Hogs.

In 1863, the year of the Battle of Gettysburg, according to the McCoy story, the McCoys turned loose some hogs which were stolen by the Hatfields.  The Hatfields indignantly denied the allegation and a trial followed.  Whatever its outcome, it was unsatisfactory to both sides.  The first bloodshed occurred soon after, when Devil Anse killed Harmon McCoy.

Occasional killings followed, and in 1882 began a romance which fanned the quiescent embers of the feudists’ hates.  Jonce Hatfield and Rosanna McCoy fell in love!  She was a daughter of Randolph McCoy; the chieftain of the McCoy clan, and Jonce had already been married.  They lived together and their families became increasingly embittered,  so that killings recurred with new vigor.

Rosanna returned to her family in Pike County during the height of the fray, but Jonce, like a true lover, continued to visit her.  He was finally captured by the men of her family, who turned him over to Sheriff’s men to be arrested for carrying a concealed gun, although they themselves were always armed.  Fearing her relatives would murder Jonce, Rosanna hastened to the Hatfields and aroused them.

Three Brothers Killed at Once 

“Devil Anse” and his son “Cap” headed a band which rescued Jonce and renewed warfare which followed resulted in the stabbing of Ellison Hatfield, one of “Devil Anse’s” sons, by four McCoys.  As Ellison lay dying Elias and Val Hatfield arrived and, finding what had happened, headed a troop of kinsmen who seized Tolbert, Pharmer and Randolph McCoy.  The Hatfields took the McCoys back to Logan County and there decided that if Ellison died their prisoners must.  Ellison died and the Hatfields killed the three brothers.

A Hatfield, sitting as coroner, pronounced the murders to have been committed by unidentified persons and the Pike County grand jury indicted twenty-three Hatfields.  No one, however would serve the warrants.  The enmity that followed resulted in an expedition to the McCoy homestead led by “Cap” Hatfield.  The home was set afire.

As Mrs. McCoy, wife of Randolph, ran out, she was knocked senseless.  Her 16-year-old daughter was shot dead and Randolph shot his way to freedom.  Calvin McCoy also was killed and victory belonged to the Hatfields.  Reprisals followed, with more deaths on both sides, and at last “Cap” and his step-son were lodged in the Mingo County jail.  “Devil Anse” tried to effect a jail delivery but failed.  Soon afterward “Cat,” with the aid of a smuggled hatchet, chopped his way out.

The Fight of “Devil’s Backbone.”

 There was fight left in the Hatfields.  A dozen of the clan, herded together, were pursued by a posse headed by Randolph McCoy and the battle which followed ended the lives of half dozen on each side, but the Hatfields, led by the valiant “Cap,” fled into the heart of their own country, where they took refuge in the “Devil’s Backbone,” a hugh crag.  The deputies closed in and opened fire, finally bringing up dynamite to blast the crag.  The blast went off and the handful of Hatfields charged their greatly outnumbered enemy.  Down toppled the “Devil’s Backbone” with a second blast but “Cap” and a few of his followers escaped.

After 1887 the feud died down.  In 1898 many of the youths of both sides went to the Spanish-American War and returned with the knowledge that the world was a larger place than they had thought.

“Cap” Hatfield Becomes Peaceful. 

“Cap,” once described as “six feet of devil and 180 pounds of hell,” became peaceful, later serving as a deputy she5riff of Logan County under J. D. Hatfield, present sheriff, his brother, and Tennis Hatfield, another brother.

“Cap,” who studied law by correspondence in his middle age, and had been an indefatigable reader, even in the early fighting days, was admitted to the bar.  He did not practice, however.  He never indulged much in reminiscence and could not be persuaded to recount his early experiences.  He once did confide to friends that many of his old-time foes believed he had a charmed life.  He said he “guessed” he was shot at about 300 times during the mountain warfare and was wounded but once.

NOTE:  It wasn’t Cap Hatfield that was called “six feet of devil and 180 pounds of hell”, it was his father, Devil Anse. 

“Capt.” Hatfield, Shot By Brother, Is Dying
September 20, 1906
The Washington Post 

“CAPT.’ HATFIELD, SHOT BY BROTHER, IS DYING
Noted West Virginia – Kentucky Border Outlaw Nears End
Said To Have Killed Dozen Men

After Being on Bad Terms for Some Time, Two Brothers Met on Railroad and Began Firing at Forty Yards.  Younger Man, a Physician, Planted Two Pistol Bullets in Feud Leader.  Special to the Washington Post.

Huntington, WV, Sept. 19 – Capt. Hatfield, the State’s most noted outlaw, who for years spread terror among the natives along the West Virginia – Kentucky border and especially to the McCoy family, is dying at Wharncliff, Mingo County, was the result of two bullet wounds inflicted by Dr. Elias R. Hatfield, his youngest brother.

Met on Railroad Track.

“Cap” and the young doctor had not been on the most friendly terms for a few weeks, but why no one may ever know.  They met this morning on the railroad track just below Wharncliff.  “Cap” as usual, carried a Winchester rifle, while the younger Hatfield had a pistol.

The men began shooting when within forty yards of each other.  The younger doctor proved the better marksman, and put two bullets directly through the chest of his outlaw brother.  “Cap”, it is said, in his lifetime has killed more than a dozen men.

For two years he had been running a “blind tiger” near Wharncliff and was unmolested by revenue men as all knew that to attempt to capture him meant practically sure death.

Dr. Hatfield Surrenders.

Dr. Hatfield has surrendered to the Mingo authorities.  He is twenty-six years old and a graduate of the Louisville (KY) Medical College.