Amazon's Anime Strike streaming platform posted the 26-episode first season of Darker than Black on Tuesday. The series is available in Japanese with English subtitles and with FUNimation Entertainment's English dub.
Anime Strike describes the story:A new and deadly breed of covert agents walks the streets. These assassins and spies wield bizarre supernatural powers to carry out the dirty work of others. One among these operatives is more mysterious than the rest - the Black Reaper. His true identity remains unknown, but as his path weaves through the alleys of Tokyo, blood is spilled on both sides of the law.
Funimation previously licensed the 2007 series, but its license expired last year so the series is no longer available on Funimation's streaming platform. Funimation first released the series on DVD singles starting in 2008, then released the full season DVD box sets in 2010 and 2011, followed a Blu-ray Disc premium edition in 2015.
The second season, Darker than Black: Gemini of the Meteor, and the OVA series are still available streaming from Funimation.
Thanks to jlaking and Billy Smith for the news tip.