Yep, I was always waiting for it to switch back to Tana (well for an episode or two anyway...)
Shame they left it -- since it just got interesting back there, and they go and build a whole new (more or less) story.

Been a while since I watched, but thought was quite clear Wakkan was a 'being' from the other side? (of what, I forget).
I think they leave a lot in this series to the watcher to complete -- lot more interesting that way at least.

I wouldn't say it's like this series - but check out 'Paranoia Agent'
Very wierd/random.