Question: Who did the warchief Red Cloud defeat in the Powder River War?

Context paragraphs:
Treaty of Fort Laramie (1868): The Treaty of Fort Laramie (also called the Sioux Treaty of 1868) was an agreement between the United States and the Oglala, Miniconjou, and Brulé bands of Lakota people, Yanktonai Dakota and Arapaho Nation signed on April 29, 1868 at Fort Laramie in the Wyoming Territory, guaranteeing the Lakota ownership of the Black Hills, and further land and hunting rights in South Dakota, Wyoming, and Montana.  The Powder River Country was to be henceforth closed to all whites.  The treaty ended Red Cloud's War.

Powder River Massacre: The Powder River Massacre, part of the Powder River Expedition, occurred on August 17, 1865, and was carried out by United States soldiers and Pawnee scouts against 24 Cheyenne people.  The incident occurred near the Powder River in Dakota Territory, in present-day Johnson County, Wyoming.

Fort C. F. Smith (Fort Smith, Montana): Fort C. F. Smith was a military post established in the Powder River country by the United States Army in Montana Territory on August 12, 1866, during Red Cloud's War.  Established by order of Col. Henry B. Carrington, it was one of five forts proposed to protect the Bozeman Trail against the Oglala Lakota (Sioux), who saw the trail as a violation of the 1851 Treaty of Fort Laramie .  The fort was abandoned in 1868 and burned by the Sioux under Red Cloud.

Oliver Red Cloud: Oliver Red Cloud (November 30, 1919 – July 4, 2013) was a chief of the Oglala Sioux.  Oliver Red Cloud is a direct descendant of Chief Red Cloud.  He was the spiritual leader of the tribe for many years and very active in tribal affairs as well as the annual pow wow.  He worked hard to instill spiritual values and rituals.  He spoke at length during the annual pow wows every August.  This pow wow of dancing and friendship is one of the largest in the USA open to all.  He became Chief of the Oglala Lakota, also known as the Oglala Sioux, in 1977 at the death of his father Charles Red Cloud.

USNS Red Cloud (T-AKR-313): USNS "Red Cloud" (T-AKR 313) is one of Military Sealift Command's nineteen Large, Medium-Speed Roll-on/Roll-off (LMSR) Ships and is one of the 49 ships in the prepositioning program.  She is a "Watson"-class vehicle cargo ship named for Corporal Mitchell Red Cloud, Jr., a Medal of Honor recipient, after whom Camp Red Cloud in Korea is also named.

Red Cloud: Red Cloud (Lakota: Maȟpíya Lúta) (1822 – December 10, 1909) was one of the most important leaders of the Oglala Lakota.  He led from 1868 to 1909.  One of the most capable Native American opponents that the United States Army faced in its mission to subdue the western territories, he led a successful campaign in 1866–1868 known as Red Cloud's War over control of the Powder River Country in northeastern Wyoming and southern Montana.  The largest action of the war, the Fetterman Fight (with 81 men killed on the US side), was the worst military defeat suffered by the US on the Great Plains until the Battle of the Little Bighorn ten years later.

Henry B. Carrington: Henry Beebee Carrington (March 2, 1824 – October 26, 1912) was a lawyer, professor, prolific author, and an officer in the United States Army during the American Civil War and in the Old West during Red Cloud's War.  A noted engineer, he constructed a series of forts to protect the Bozeman Trail, but suffered a major defeat at the hands of the warchief Red Cloud.

Powder River Station-Powder River Crossing: The Powder River Crossing, officially known as Powder River Station-Powder River Crossing (48JO134 and 48JO801), is an abandoned settlement located on the east bank of the Powder River in southeast Johnson County about twenty-four miles east of Kaycee, Wyoming.  It developed after a wooden toll bridge was built across the Powder River in 1877, at a site that was originally used as a ford.  With crossing secured, a settlement developed here in the late 19th century, incorporating a stage stop on the Bozeman Trail.  The site is notable for having well-preserved wagon ruts from the pioneer era.

Red Cloud's War: Red Cloud's War (also referred to as the Bozeman War or the Powder River War) was an armed conflict between the Lakota, Northern Cheyenne, and Northern Arapaho on one side and the United States in Wyoming and Montana territories from 1866 to 1868.  The war was fought over control of the western Powder River Country in present north-central Wyoming.  This grassland, rich in buffalo, was traditionally Crow Indian land, but the Lakota had recently taken control.  The Crow tribe held the treaty right to the disputed area, according to the major agreement reached at Fort Laramie in 1851.  All involved in "Red Cloud's War" were parties in that treaty.

Powder River Expedition (1865): The Powder River Expedition of 1865 also known as the Powder River War or Powder River Invasion, was a large and far-flung military operation of the United States Army against the Lakota Sioux, Cheyenne, and Arapaho Indians in Montana Territory and Dakota Territory.  Although soldiers destroyed one Arapaho village and established Fort Connor to protect travelers on the Bozeman Trail, the expedition is considered a failure because it failed to defeat the Indians and secure peace in the region.

Supporting paragraphs: Henry B. Carrington Red Cloud's War
Answer: Henry Beebee Carrington