All right. You caught me.
When I was coming up with the name for the demon, I originally had something a little different. It sounded German, however, and I know the word "nacht," so I decided to flip open a German/English dictionary and see if I could come up with anything of a similar sound that might have some meaning.
Thus, I knew that "taufen" was baptism and "nacht" was night, and I put them together deliberately. I knew it wouldn't be proper German, since I don't know the language, but I liked the feel of having the two words together.
For the record, though, I wasn't thinking of it as a "night of baptism" so much as the notion of someone being baptized by darkness, rather than water.