The original collective names for the ancestors of the Ijos were “Kumoni” and “Oru”, survivals of the ancient terms of “Khem-Anu” or “Khem-Onu”, and “Horu” of the ancient Nile valley civilisations of Khem or Kemetu (ancient Egypt) and Kush (ancient Sudan). The Kumoni-oru derived from ancient Egypt via Ife, while the Oru derived from ancient Sudan. Now the earliest ancestors of the Ijos, the “Orus” or “Tobu-Otu”, migrated from the lake Chad aquatic civilisation of Daima region (c 5000-2000 BCE). Their settlement in the delta was from the earliest of times. Unfortunately not much is known about this period, only that traditionally it is said that these early ancestors “dropped from the sky” (i.e. to say the Orus were of divine origin), and were devotees of spiritual culture that made much use of the waters (hence the mermaid and water people legends “Beni-Otu”) They were later to be joined by other ancestors “Kumoni-Orus” from about 400 CE, and 650 CE (AD), who, after settling first in the Nupe and Borgu regions, then the Ile-Ife region, moved to the Benin region via Nupe, and Ife. In the Benin region they eventually settled and launched expeditions into the Niger Delta, where they came across remote settlements of the Orus, whom they termed “ancient people”. But because they were also ultimately Oru, from the beginning they established communities as one people. The Ijos were known by the two names of Kumoni or Oru up till the time of the 19th century. European visitors noted the name Oru as a distinct term for Ijaw. Likewise the compilers of the Izon/English dictionary noted that “to speak Kumoni is to speak pure Izon language”. The term Ijo (Ijaw) or Izon evolved as the name of the whole ethnic nationality through time, even though as a personal name it derived from one ancestor who was known as Ujo, whom as we have previously mentioned, represents the time when the Ijos evolved as a distinct separate people from their neighbours.

The original ancestral settlements founded by the proto-Ijos in the central delta were, Agadagba-bou (first home of Ujo in the central delta), in Igbedi Creek, Isoma-bou along the Nun river, Opuan-bou in the same area, and Orubiribua-bou, also in the same area, and Abo, with its villages, further up the Niger.

When they came and settled in the central delta, the ancestors personified by Ujo, after establishing their authority over preexisting settlements (central delta), instructed an expedition force to go and guard the mouth of the delta and other important places along the coast as stipulated by his father King Adumu. These people became the ancestors of several Izon clans. Keni Opu Ala or Keni-Ala, the holy seer (Asain) of Adumu, the Supreme Intelligence symbolized by the sacred serpent python, was the ancestor who founded Ke or Keni and its daughter towns. Kula and Bille were also founded in this way. Ogulagha and Iduwini, were founded as a result of proto ancestors settling in the western coastal delta, to guard that region. Oguru (alias Kala-Ogbo who gave his name to Warri region (Ogbo Ijo) settled the area now known as Warri region, these ancestors were to be joined by people from Oporoma. Others such as Kuru, founded the Kru people (they seem to have been proto-Ijos), who eventual migrated to the present day Liberia region, while some ended up settling in present day Ghana region.

After many years of settlement Ujo left his headquarters in Igbedi creek in charge of the Agadagba of Egbesu (military officer), and decided to go back to Otu-Ife. He traveled with nine companions including his grandson Apoi (Opoi) the son of Kala-Okun. Without a skilled astronomer they got lost and decided to settle in a creek near the vicinity of the Nun river. It was here they founded the village of Apoi. Ujo made his permanent home with his grandson Apoi at the quarter now known as Okoto-aja. It was here that he died and was buried. Ujo who was titled Kalasuo, gave the title to his grandson Apoi, since then the rulers of Apoi clan have been titled “Kalasuo”. From the central Apoi, a section migrated to the western delta, to found Apoi Ijo of the Ondo region. Also from the central Apoi, was founded Akassa clan along the coast.

The ancient town of Ujo-Gbaran or Gbaran for short was founded by Gbaran an elder son of Ujo. Gbaran was given the scepter of Ujo on the death of his father. Later on his descendants went and founded the town of Oporo-aja (Oproza) in the western delta region of Escravos, to give birth to the Gbaranmatu and also Arogbo in Ondo area. Children of Ujo, Olodi and Oporo, went and established a common settlement, from which descendants founded Oporoma and Olodiama clans. From Olodiama in central delta, ancestors left to found Olodiama in the western delta near Benin, and also ancestors left to found Olodiamabiri and Onyomabiri and other towns, to form Nembe clan. From Agadagba-bou was also founded Ogbia (Ogbo-Oyan) clan who are the descendants of Oyan. From the same Agadagba-bou, led by Opu-Ogbo, was founded, Isoma-bou or Opuan-bou, from which ancestors later migrated to found, Ekpetiama, and Seimbiri clans.

The last to leave the ancient town of Agadagba-bou, were the ancestors of the Opukuma, Kolokuma, Tarakiri and Andoni. Opu-Okun was the ancestor of the Opukuma, while Kala-Okun was the ancestor of the Kolokuma, both were children of Ujo by the same mother. Tara a younger child of Ujo was the ancestor of the Tarakiri, while Ayama the son of Tara was the ancestor of the Andoni in eastern Ijo,. The Andoni (ruler known as the Andoni-Oru) town of Asarama was founded by Asara or Assa an ancient ancestor descendant of Ayama.. At that remote period most of the ancestors lived in Igbedi creek at Agadagba-bou and the immediate environs of the Nun river. Afterwards their descendants migrated all over the delta. Lastly Abowi, the Asain (seer) of Ujo who led the migration from Otu-Ife or Ile-Ife, journeyed up the river Niger to establish a number of villages which gave rise to Abo and Atani (ruler known as the Atani-Oru). Abo or Aboh and Atani no longer speak Izon language.