Short answers, pulled from the story.
Genghis Khan was born between 1155 and 1167, likely in 1162, on the banks of the Onon River. He was the eldest son of Yesügei, a Mongol chieftain of the Borjigin clan, and Hö'elün, a woman from the Olkhonud clan.
Genghis Khan faced a childhood of brutal abandonment after his father Yesügei was poisoned by Tatars when Temüjin was only eight years old. The clan abandoned his widow and children, forcing the young Temüjin to kill his older half-brother Behter to secure his position as the head of the family.
Genghis Khan died on either the 18th or the 25th of August 1227, though the exact nature of his death remains a subject of intense speculation. Historical accounts suggest he suffered from an illness, possibly malaria, typhus, or bubonic plague, or was struck by lightning, while legends claim he was injured during sex with the Xia emperor's wife.
Ögedei was recognized as the heir to the Mongol throne and crowned as khan in 1229 after a kurultai attended by his brother Tolui. Tolui served as regent after Genghis Khan's death, establishing precedents for mourning and succession that ultimately led to Ögedei's appointment.
The Baljuna Covenant was a pledge of loyalty sworn by Temüjin to his faithful followers at an unidentified lake or river after his defeat at the Battle of Qalaqaljid Sands in 1203. This oath-takers were a heterogeneous group from nine different tribes united by loyalty to Temüjin and to each other, forming a model for the later empire.
Genghis Khan reorganized Mongol society into a military decimal system where every man between the age of fifteen and seventy was conscripted into a tumen, a unit of a thousand soldiers. This system replaced old tribal identities with loyalty to the Great Mongol State and included a bodyguard corps that served as a military academy and center of governmental administration.