i figured it out!

after a long and troubling period after i saw Marebito, i have finally come to a sort-of conclusion about what it all meant...

The guy was married, divorced probably, and the girl who was his daughter was actually the girl he was spying on at the very beginning - who lived in the building opposite and apparently had some kind of drug problem.

So, when he ventured down into the subway tunnels, that was figurative. That's why all the scenes there are very choreographed, the dialogue with the dead guy is very flowery and intellectual, and it all looks like some kind of dream. When he finds F, he is really finding his own daughter. The only way I can explain why she would act like she does is because a) she is messed up from drugs and her memory was somehow erased or b) she had that disease where she can't go out in sunlight and has to drink blood. Or maybe some combo of the two. This is where I get a little hazy...

So he is such a wacko that he doesn't remember who she is. Doesn't remember his wife, or anything. The blood from the baby bottles is symbolic of his nurturing her but with the added layer of eroticism.

At the end, I am guessing that he has died, as she's leading him down the stairs. Because if he cut his tongue, saliva is an anti-clotting agent and so without medical care he would almost certainly have bled to death (thus fulfilling his earlier aspiration of 'feeding her until she was satisfied')

I am not quite sure why he looks so horrified at the end. Maybe it's because he realized what he'd done to her?

As for the Deros - they were a symbol. When the homeless guy tells him at the beginning "they'll suck your blood dry" - that's obviously his daughter, F. Literally she's his daughter, but symbolically she's a Deros, existing only to feed. She moves like they do and everything.

At the end, when he sees the two Deros in the street, leads me to believe that he himself was actually a Deros on a figurative level. He didn't drink blood, but he fed off people's fear - like the suicide guy at the beginning - and ended up spilling blood in his search for terror.

Does this make sense to anyone other than me? I still don't know why he was so scared at the end - especially when he was all calm and cool throughout the rest of the movie.