Since Marvel has not yet confirmed any roles beyond Boseman playing Black Panther, these predictions and this casting should be taken with a grain of salt. You can read the complete casting notice below.
• ULYSSES KLAW (played by Andy Serkis) – Murderer and betrayer of T’Chaka and personal archenemy of T’Challa. A powerhouse with near-absolute control of sound.
• MONICA LYNNE – A singer who saved T’Challa from drowning after being bested by Killmonger. His longest love interest, whom he pledged eternal devotion towards.
• EVERETT K. ROSS – A United States State Department employee, whose job was to escort foreign diplomats on American soil. His world changed forever when he was assigned to T’Challa, the Black Panther, the ruler of Wakanda.
• N’GASSI – Adviser to T’Challa, acting regent when he goes away on missions.
• OKOYE – One of the former Dora Milaje, a ceremonial betrothed/bodyguard of T’Challa. Okoye is of the J’Kuwali tribe and acted as a traditional, proper concomitant to the king, speaking only to the king and only in Hausa, an African dialect not widely spoken in Wakanda and thus affording the king and his wives a measure of privacy.
• QUEEN DIVINE JUSTICE – The street-smart queen of the Jabari tribe of Wakanda raised in Chicago, and former Dora Milaje (ceremonial betrothed/bodyguard) of T’Challa. She originally went by the name Chanté Giovanni Brown.
• W’KABI – T’Challa’s competent second-in-command, completely loyal to his liege.
• ZURI – A grumpy and gigantic elderly warrior. A close friend of the late T’Chaka, and one of T’Challa’s most trusted advisers.
• ACHEBE/REVERAND ACHEBE – A poor farmer somewhere in South Africa, Achebe sold his soul to the demon Mephisto. He is portrayed as a grinning, unpredictable, lunatic, warrior-mystic, regularly talking to his hand-puppet Daki with delusions that it’s truly alive, and engineering complex plots of social unrest for profit or entertainment.
• ERIK KILLMONGER – A powerful warrior and strategic genius in politics and economics.
• MALICE – Wakandan Mutate with superhuman strength, speed, and agility. She is a former Dora Milaje (ceremonial betrothed/bodyguard) of T’Challa.
• MAN-APE – Ruler of the Jabari Tribe a recognized micronation within Wakanda’s borders. M’Baku was Wakanda’s greatest warrior second only to the Black Panther. He plotted to usurp the throne with the help of the outlawed White Gorilla cult who were ancient rivals of the Black Panther cult, which basically made them heretics since Panther worship is the state religion. Founding member of the “Pan African Congress on the Treatment of Superhumans”.
• WHITE WOLF – T’Challa’s adopted elder brother and the former leader of the Hatut Zeraze, the espionage elite police of Wakanda. Exiled by T’Challa, due to using torture and assassinations in his zeal to root out potential threats to national security.