The term "Ebony Kingdom" is coined by the Laibon, the vampires of Africa and describes their realm of influence. The Ebony Kingdom is divided into 11 lesser kingdoms, each controlled by a Guruhi who in turn hands fiefdoms to the local Magaji's, who rule their domains in his name. Most Laibon have no idea who their current king is and it happened that an entire kingdom changes its owner without anyone noticing. Sometimes, the king banishes an magaji who has evoked his ire, but in most cases, another king will be happy to put the banished into his service.
Rulership within the Ebony Kingdom is a thankless and confusing job. Domains are fractured, overlapping and it happened that two magaji ruled over the same domain without noticing or a domain remains without an ruler for decades until the king notices it. Their kings, whom many Laibon doubt to even exist, encourage this infighting, as it turns the attention of the ambitious magaji to potential rivals instead of usurping their rule.
As to the fluid borders of the different domains and the absolute secrecy of the Guruhi kings, it is nearly impossible to pin down a map of the complete Ebony Kingdom, but it seems certain that it stretches over the whole sub-Saharan African continent.