How many books will there be in the Meta series?

There will be a fourth book for sure since there are still some unanswered questions that I want to answer and some characters and ideas that I want to explore further. Past the fourth book, I hope to still write more in the series as long people are still enjoying it.

Are their going to be German language versions of other books besides Meta?

I would love to translate them all, but the truth is that the first book hasn't recouped its translation costs yet so until that happens there aren't any plans to translate the others unfortunately.