On the plane...
On the island...
S1 - S2 - S3 - MP - S4 - S5 - S6
Daniel is the son of Amina and is an altar boy in Yemi's church. He continues on there after Yemi goes missing and Eko replaces him. He tells Eko that he's not supposed to wash his hands in the holy water.
After Eko kills the thugs that attacked him in the church, Daniel asks him: "Are you a bad man? My mother says you are a bad man." Eko retorts, "Only God knows." On the Island, Eko recalls this conversation and tells the image of his brother that he wish he had told this boy that he had no regrets about what he has done in his life, because he only did what he had to to survive and save his brother as a child.
Daniel is one of the visions that Eko has on the way to the Beechcraft. He simply says to Eko, "Confess." ("The Cost of Living")