Erik Stevens was born in Oakland, California to the Wakandan prince N'Jobu, and was given the Wakandan name N'Jadaka. Due to his mother being incarcerated, Stevens was raised by N'Jobu, and was told stories on Wakanda's true nature. Wanting to have his son be able to visit Wakanda someday, N'Jobu gave Stevens a War Dogs Tattoo. One night in 1992, Stevens was playing basketball with friends when he saw a Royal Talon Fighter above the apartment. Going inside the complex, he found his father dead on the floor with panther claw markings in his chest. Realizing that the Black Panther, who was his father's brother T'Chaka, had committed the murder, Stevens cradled his father in tears before getting his father's diary and maps, containing information and coordinates on Wakanda.
With no parents, Stevens lived alone and in poverty as a child, and experienced firsthand oppression on African-Americans. After reaching adulthood, Stevens joined the United States Naval Academy and graduated at age nineteen, then went to MIT for grad school. Wanting to make his father's dream of Wakanda using vibranium to eradicate the poverty and oppression of African-Americans true, he decided to avenge his father by killing T'Chaka and his son T'Challa, and claim his blood right as the next ruler of Wakanda. Stevens then joined the United States Navy SEALs and was assigned to a JSOC ghost unit that assassinated high profile targets and aided the CIA in destabilizing foreign countries. His savagery during his time in the unit caused his to be dubbed "Killmonger."
Days after the death of King T'Chaka in 2016, Killmonger decided to put his plan into action and seize the throne of Wakanda. Killmonger made a deal with Ulysses Klaue, an arms dealer his father had worked with, and located a vibranium Warhammer in the Museum of Great Britain. The robbery was a success, but Klaue was captured by T'Challa after his fail attempt to sell the vibranium to Agent Everett Ross in South Korea. Realizing this, Killmonger rescued Klaue from T'Challa, Okoye, Nakia, and Ross.
Even though Killmonger had worked with Ulysses Klaue and had also rescued him, he ended up shooting and killing him in order to gain the Wakandan's trust. Killmonger brought Klaue's body to Wakanda and presented it to W'Kabi. W'Kabi, already disappointed with T'Challa for not managing to bring Klaue to justice for his crimes, brought Killmonger to the King and his council. The meeting began with mutual hostility on both sides, Killmonger for his historical grudge against Wakanda and its people and T'Challa and the council for his theft of Klaue from their custody, and Killmonger stated his desire to usurp the throne and become king. The elders of the council immediately burst out laughing at this notion, but all present were stunned into silence when Killmonger revealed that he was in fact the son of Prince N'Jobu and thus entitled to challenge for the throne. Ramonda and the River Tribe Elder both attempted to convince T'Challa not to accept the challenge as Killmonger was an outsider and the challenge itself would take many weeks to prepare but T'Challa, acknowledging the traditions and that Killmonger did have legitimate reason to be angry at Wakanda and wish to claim the heritage he'd been denied, accepted the challenge.
Due to the short notice of the challenge, the attendance was considerably lesser than T'Challa's own incoronation with only his immediate family, the Tribal Council, several Dora Milaje and Zuri and a priestess being present at Warrior Fallsto witness the duel, Killmonger took his shirt off, bearing his scars, stating that each scar stood for a life he had taken, lives in the United States of America, as well as Afghanistan, Iraq and even fellow Africans on the continent itself. T'Challa offered Killmonger one final chance to stand down and resolve things peaceably, but was refused and thus the challenge began. Killmonger had the upper hand in the fight, as the duel required the Black Panther to be stripped from his powers in order for the duel to be fair. While T'Challa managed to gain an initial advantage by knocking Killmonger down and even slashing his face, his reluctance to kill his cousin worked to his disadvantage. Killmonger inflicted numerous wounds on T'Challa by slashing his thighs and chest before stabbing him in the stomach.
Right before Killmonger could deal the killing blow, Zuri stepped in and intercepted the blow. Zuri, having been sent by T'Challa's father, King T'Chaka to America to keep an eye on Killmonger's father N'Jobu and had been there during Killmonger's childhood, begged Killmonger to take his life and spare T'Challa, telling Killmonger the truth of his father's death. In rage, Killmonger murdered Zuri by stabbing him in the heart with his own weapon, calling him "Uncle James", and T'Challa screamed in despair for his death. Using T'Challa's vulnerability to his advantage, Killmonger went on to punch the King, mocking him and the fact that he was too weak. In the end, Killmonger picked T'Challa up on his shoulders and threw him down the waterfall to his alleged death, leaving Killmonger to be the new King of Wakanda.
Killmonger went through the coronation ritual, consuming in the Heart-Shaped Herb and met N'Jobu in the Ancestral Plane. Becoming the Black Panther, Killmonger ordered that the herb gardens be burned in order to ensure there would be no future Black Panther kings. The senior prestess protested, citing tradition, but Killmonger lifted her by the throat and strangled her until she fearfully agreed, horrifying all the other priests into obeying as well. Killmonger, now the king of Wakanda and supported by W'Kabi and his Border Tribe army, prepared shipments of Wakandan weapons to be distributed to operatives around the world, so they may spread it to other people of African descent so that they may fight back against their oppressors.
The Jabari Tribe had found T'Challa in the freezing rivers where they fish and brought him back to their domain. M'Baku decided to save his life as repayment for his mercy at the falls earlier. In their displeasure manner, Nakia, Ramonda, Shuri, and Everett Ross escaped Wakanda while Killmonger consolidated his power. With T'Challa comatose and stabilized only by the surrounding snow, Ramonda remembered to use the one Heart-Shaped Herb they stole to bring him back.
Awaking in the Ancestral Plane again, T'Challa was greeted by T'Chaka and invited to join him and the rest of his ancestors. Instead, T'Challa was furious at his father for what happened to his uncle and cousin and angered by the other Black Panthers for how their strict isolationism has led to suffering around the world. T'Challa declared his work wasn't done yet and woke to the relief of his loved ones. T'Challa thanked M'Baku for saving his life and requested that he and the rest of the Jabari help overthrow Killmonger. M'Baku declined, as he had already repaid his debt to T'Challa. The group left the tribe, with Shuri giving T'Challa his Panther Habit for the coming battle.