In Delta, you have ethnicities that have a multiplicity of influences--Benin, Yoruba (Lukumi), Igala, and Igbo.
The Itsekiri's affinity with Yoruba is clear. The Urhobo's cultural proximity to Benin is equally conspicuous. And there are several communities who have gradations of connection to their Igbo neighbors across the Niger.
To add to the complication, some ethnicities who have been influences by multiple political and linguistic currents insist on and emphasize one of these influences over the others, even though their names may point in a different direction.
You might see a Delta person with the name Chukwuma Anielo, but he'll fight you for calling him Igbo. He'll educate you on his and his community's Benin origins even though his language, though an amalgam of different languages, has a dominant Igbo or Igboid inflection.