St&rs 1-22
This is a series where the focus pretty much has to change at some point. Could really go in any direction depending on the alien's plan. It's definitely interesting, but I hope it isn't cryptic stuff for another 100 chapters (provided it makes it that far).
I sometimes wonder if the author planned to make the series a battle manga at one point. I just never saw the mystery to last more than 50 chapters.