This small African country has the largest deposit of Wakandan Vibranium in the world.
T'Challa is the son of T'Chaka, who was the Black Panther before him. In the distant past, a massive meteorite comprised of the sound-absorbing mineral vibranium crashed in Wakanda, and was unearthed a generation before the events of the present-day. Knowing that others would attempt to manipulate and dominate Wakanda for this rare and valuable resource, T'Chaka concealed his country from the outside world. He would sell off minute amounts of the valuable vibranium while surreptitiously sending the country's best scholars to study abroad, consequently turning Wakanda into one of the world's most technologically advanced nations. Eventually, however, the explorer Ulysses Klaw found his way to Wakanda, and with lies and subterfuge covered up his work on a vibranium-powered, sound-based weapon. When exposed, Klaw killed T'Chaka and many other Wakandans, only to see his "sound blaster" turned on him by a grieving T'Challa, then barely a teenager. Klaw's right hand was destroyed, and he and his men fled. 
Vibranium radiation has permeated much of Wakanda's flora and fauna, including the Heart-Shaped Herb eaten by members of the Black Panther Cult, and the flesh of the White Gorilla eaten by the members of the White Gorilla Cult.
After the vibranium meteor fell, a number of Wakandans were painfully mutated into demon spirits and began attacking their fellow Wakandans. T'Challa's ancestor, Bashenga became the first Black Panther and closed the vibranium mound to outsiders, forming a religious cult that guarded the mound and fought to keep the "demon spirits" from spreading across the kingdom.
The Black Panther is a ceremonial and religious title given to the chief of the Panther Tribe of the fictional African nation of Wakanda. In addition to ruling the country, he is also chief of its various tribes (collectively referred to as the Wakandas). The Panther uniform is a symbol of office as well as a religious vestment.
As part of the cult's ceremonies, A chosen Black Panther is entitled to the use of a heart-shaped herb that grants the person who consumes it enhanced strength, agility, and perception.
Wakanda evolved from a hunter-warrior society, and was traditionally ruled by its greatest warrior. The dominant Black Panther cult outlawed the rival White Gorilla cult's worship in Wakanda.
M'Baku was one of Wakanda's greatest warriors, second only to T'Challa, the Black Panther himself. While T'Challa king of Wakanda, was on a several month leave of absence from Wakanda, the ambitious M'Baku plotted to usurp the throne.
M'Baku flouted T'Challa's edicts and revived the White Gorilla cult, killing one of the rare white gorillas living in the jungles near Wakanda. M'Baku bathed in the gorilla's blood and and ate its flesh which "mystically" conferred the gorilla's great strength upon M'Baku.
Sekmeht the Lion God could possess the form of any human worshipers or the bodies of those sanctified and sacrificed by its worshipers, it transformed these subjects into human avatars of itself. He has a number of other powers, some of which he has demonstrated. Sekmeht could grow in size, move at rapid speeds, teleport itself and others, and alter its specific density. The Lion God possessed superhuman strength and durability, and it was immortal. It can manipulate the minds of the weak willed.
Little is known of the past history of the Lion God. It had apparently lost many worshipers over the years to the Cult of the Panther God, despite the fact that Sekmeht physically manifested before its followers, and the Panther God only appears to its priests.