For thirty years, your father was in power and did nothing. With you, I thought it would be different, but it is more of the same.
~ W'Kabi losing his faith in T'Challa.
W'Kabi is a supporting antagonist of the 2018 Marvel film Black Panther. He is the head of security for Wakanda's Border Tribe as well as the best friend of T'Challa who would later turn on him in favor for Erik Killmonger.
He was portrayed by the Academy Award nominated actor Daniel Kaluuya, who also played Black Death in Kick Ass 2.
Being Friends with T'Challa
W'Kabi started out as a best friend to T'Challa, and the lover to the Dora Milaje general Okoye. However, W'Kabi lost his parents when Ulysses Klaue infiltrated Wakanda and stole vibranium (thanks to N'Jobu's treason).
Many years later, after T'Challa had been crowed king of Wakanda, he was informed that Klaue was planning on selling a piece of vibranium he had stolen from a British museum. As such, T'Challa planned to go after Klaue, which was encouraged by W'Kabi, who told his friend to either apprehend Klaue or kill him.
T'Challa then vowed to W'Kabi that he would track down Klaue and make him answer for his crimes against Wakanda.
Though T'Challa was able to help capture Klaue, Killmonger successfully freed Klaue from custody, only to later kill him in order to gain access to Wakanda. Feeling disgraced over T'Challa's failure, W'Kabi lost his faith in him. Eventually, Killmonger arrived at the Wakandan border bringing Klaue's body, which motivated an impressed W'Kabi to ally himself with Killmonger.
W'Kabi then reveals his new allegiance to T'Challa by revealing Killmonger's true heritage to the Council as Erik challenges the latter to a duel. After T'Challa lost, W'Kabi watches in satisfaction as Killmonger throws T'Challa into a waterfall to his death. W'Kabi then proceeded to aid Killmonger's next plan in providing vibranium weapons to the Wakandan spies around the world so Wakanda could begin taking power.
Final Battle and Defeat
However, T'Challa is rescued by the Jabari tribe (led by M'Baku), thanks to a debt that T'Challa paid for sparing his life. After being revived by Nakia, Shuri and Ramonda, T'Chall returns to stop Killmonger, who sends W'Kabi and his men to engage in battle against the Dora Milaje. During the battle, T'Challa begs his former friend to call his men off, but W'Kabi refuses and calls several rhinos to his aid, turning the tides of the battle.
As his tribe corners the remaining resistance, W'Kabi watches in shock as M'Baku brings in the Jabari tribe to help, again shifting the battle. W'Kabi attempts to ram into M'Baku using his rhino, although Okoye gets in the way, causing the rhino to stop and affectionately lick her. Okoye then orders W'Kabi to lay down his weapon, saying that she would rather kill her former love than risk the sake of Wakanda's protection. Upon looking over the bloodshed of the battle and realized what he has done, W'Kabi complies and his forces stand down as well.
It can be implied that W'Kabi is currently imprisoned for his treachery against T'Challa following Killmonger's death and M'Baku would later take W'Kabi's place in the Council.