[Teaser website] The publisher for Black Desert Russia was announced via a live broadcast (still airing at time of posting) from Moscow Cyber Stadium, together with representatives from Korean developer Pearl Abyss. GameNet.ru is the publisher, and not Mail.ru as I expected.
Some of the games under GameNet.ru include AIKA Online, Combat Arms, and a couple other titles from China. Black Desert seems to be the portal’s first mega title. From the livestream, it seems the client is still being localized, as seen from some of the wording symbols.