Yup.
After reading through the ongoing conversation about Sekai, something's occurred to me.
We never experience her directly -- the way we have, say, Nikki, Noriko, and Maya in what seem to be actual flashbacks of past events. When she shows up, either she is a figment of his imagination/projection of his unconscious mind or she's a spirit/demon/ghost haunting him (depending on how you look at the events of the game).
Either way,
that's not actually Sekai. The character we see is an expression of all of Akira's own incredibly complex, f)#)#ed up feelings about his brother's wife.
We have to assume (because the game gives us no reason not to) that she actually seduced him as a boy -- but even that could be a fantasy. We're so far inside of Akira's head, it's impossible to know. Any guesses we make could just be... pareidolia.
ETA: Though... she did write some creepy-ass poetry, which Wakana, Otoha, and (apparently) Ami have all read. It's not
just in Akira's head. So there's that.