It’ll have the original Japanese language track with German subtitles as well as a German language dub track.
With this series is now out of print in North America, German distributor Peppermint Anime recently lined up the first season of Darker Than Black for release on Blu-ray.
Ahead of that we now have the fourth dub clip from it that shows off the German language track, which really does work in some ways that you might not expect.