According to the publisher's summary, Oscar Wilde noted in a letter that:
“Basil Hallward is what I think I am: Lord Henry what the world thinks me: Dorian what I would like to be—in other ages, perhaps.”
Basil Hallward is the artist who paints the picture of Dorian Gray. Lord Henry is Dorian's corrupter.
I'm only 20% in and I'm already finding Lord Henry's company tiresome. He never met an epigram he didn't like, as long as it was his own. His opinions are clever but facile, flashy rather than substantive and mask the fundamental dishonesty of his interior monologue.
Epigrams are fine in a play but having to listen to them all day long would be enough to make you shun a man.