Well, the synopsis of episode 5 is already up here along with the characters section updated. Information about two new characters Norio and Lebanon have been added. Read them here, you can find them being the first two of the last row.
A special web radio called Darker Than Black Backstage Pass, hosted by Hei’s seiyū (Hidenobu Kiuchi) and Suō Pavlichenko’s seiyū (Kana Hanazawa) has been added to the Special section here. Click ‘Vol.1 を聴く(WMP56k)’ and the radio episode will be streamed in your Windows Media Player.
New episodes of the radio will be randomly added, it’s unclear whether they’ll keep the old episodes up so listen to them while you can.