Bo'orchu (Mongolian: Боорчи, Boorchi) was one of the first and most loyal of Genghis Khan's friends and allies. He first met Genghis as a boy, when Temujin was looking for his stolen horses. He helped to win back the horses, and returned with Temujin to his father, Nakhu Bayan, who scolded him, having feared he was dead. Later, Temujin sent Hasar to get Bo'orchu and bring him to Temujin's camp.

He was sent to spy on the Merkits with Belgutei and Jelme after Temujin's flight from them when he lost Borte. After Genghis's appointment to Great Khan of the Mongols, he was made head of Genghis's followers along with Jelme. He was rewarded again after Genghis became Gurkhan.

When Genghis was at Dalannemurges to fight Tatars, heavy rain fell and Bo'orchu stood over Genghis with a felt sheet to shelter him. Genghis later rewarded Bo'orchu for this deed, claiming he only moved his feet once during the night. Bo'orchu was later shot off his horse during the battle of Khalakhaljid Sands. He stole an enemy horse and returned the next day, helping to find the enemy position. Bo'orchu was one of Ogedai's most trusted friends.

Genghis Khan (/ˈɡɛŋɡɪs ˈkɑːn/ or /ˈdʒɛŋɡɪs ˈkɑːn/,Mongol: [tʃiŋɡɪs xaːŋ] ( listen); 1162? – August 1227), born Temujin, was the founder and Great Khan (emperor) of the Mongol Empire, which became the largest contiguous empire in history after his death.

He came to power by uniting many of the nomadic tribes of northeast Asia. After founding the Mongol Empire and being proclaimed "Genghis Khan", he started the Mongol invasions that resulted in the conquest of most of Eurasia. These included raids or invasions of the Kara-Khitan Khanate, Caucasus, Khwarezmid Empire, Western Xia and Jin dynasties. These campaigns were often accompanied by wholesale massacres of the civilian populations – especially in Khwarezmia. By the end of his life, the Mongol Empire occupied a substantial portion of Central Asia and China.

Before Genghis Khan died, he assigned Ögedei Khan as his successor and split his empire into khanates among his sons and grandsons. He died in 1227 after defeating the Western Xia. He was buried in an unmarked grave somewhere in Mongolia at an unknown location. His descendants went on to stretch the Mongol Empire across most of Eurasia by conquering or creating vassal states out of all of modern-day China, Korea, the Caucasus, Central Asian countries, and substantial portions of modern Eastern Europe, Russia and the Middle East. Many of these invasions resulted in the large-scale slaughter of local populations, which have given Genghis Khan and his empire a fearsome reputation in local histories.