According to an unnamed source, not only will Dark Souls 3 be revealed at E3 2015 - it will be directed by Hidetaka Miyazaki himself.
E3 begins in a mere two weeks, at which point gamers will be drowning in new game announcements, trailers, and previews. It also means you should expect rampant speculation around which games will be revealed, and according to sources at VG24/7 Dark Souls 3 will be one of them. Of course, the successful Dark Souls series getting a sequel isn't so surprising - but the real twist would be original director Hidetaka Miyazaki returning to the franchise after his work on Bloodborne.
At this point, it's worth remembering that until we receive confirmation from Sony, Namco, or From Software, this is technically still a rumor. For example, we don't have any details on what features Dark Souls 3 would have or what will make its brutal difficulty curve stand out for a third outing.
That being said, Miyazaki's return would be an incredibly promising detail. After directing the original Demon's Souls and Dark Souls Miyazaki moved into a supervisory role, opting to instead direct the spiritual successor Bloodborne. Even though Dark Souls 2 was still a critically acclaimed game, some fans found notable differences from the original such as lackluster boss fights. Miyazaki could very well bring those fans back into the fold, where they'd happily be crushed to death by countless horrific monstrosities.
Regardless, we won't know for sure until Sony's E3 press conference on Monday, June 15. Here's hoping that whatever direction Dark Souls takes is equal parts riveting and punishing.