Note that both Hebron (where Sarah lived) and Beersheba (where Keturah lived) are in Idumea. Abraham's territory extended between the settlements of his two wives and was entirely in the region the Greeks called Idumea.
"Edo monarchs demonstrate strong affinity with ancient Egyptian Gods and Pharaohs, with which they share identical authority, grandeur and a great deal of reverence from their subjects. Like the Pharaohs, Idu (Edo) monarchs are God-kings. Because they are God-kings and God-sons, they are considered divine and worshipped by their subjects, who speak to them always with great reverence, at a distance, and on bended knees. Great ceremonies surround every action of the Edo king. The kings of Benin (Bini) also adopt grand Osirian titles of the ‘Open Eye,’ signifying omniscience and omnipotence. Edo monarchs, when they transit to the beyond, are, like the Egyptian Pharaohs, set up in state, in a linked series of underground chambers, surrounded with their paraphernalia of power, and all of the items they would require for their comfortable sojourn in the ethereal world" (From here.)
Edo, Edomite, Idoma and Idumea are related words. The Greeks called the inhabitants of this region "Idumeans" (people with a reddish skin tone, like the Igbo of Benin). The ancient name of Edo is Idu. Idu was the progenitor of the Edo or Idoma. Hence the expression: “Iduh the father of Idoma.” The royal lines of the Edo have been orally transmitted. Iduh begot six sons: Ananawoogeno who begot the children of Igwumale; Olinaogwu who begot the people of Ugboju; Idum who begot the people of Adoka; Agabi who begot the people of Otukpo; Eje who begot the people of Oglewu; Ebeibi who begot the people of Umogidi in Adoka, and Ode who begot the people of Yala.
A Nabataean bronze object has been found in Wādī Mūsā, near Petra. The inscription mentions a priest and his son and is dedicated to Obodas the god in Gaia. Gaia was in the mountains to the east of Petra. The text is dated to the reign of the last Nabataean king, Rabbel II (70–106 AD). Obodas, the first ruler of Petra in Edom, took his title from the Edo name for ruler which is Oba. It appears that the Edo conception of the deified ruler was found among the Edomites of Petra. This title was used also among the Ainu and in the history of Japan "obitos" refers to regional rulers.
The prophet Obadiah was from Edom, according to the Talmud, and said to have been a friend of the Horite ruler Job. Genesis 36 lists the Horite ruling family of Edom. Among them were two Horite rulers named Esau, as shown in the diagram below.
Related reading: Solving the Ainu Mystery; Petra Reflects Horite Beliefs; The Edomites and the Color Red; Why Does Genesis Speak of Gods?