According to multiple sources, both in development and retail, in the next few hours Nintendo will announce a Nintendo Direct Mini to air shortly afterwards showing 2018 software for Switch. As part of this Nintendo Direct, Dark Souls Remastered will be revealed, updating the original game to be playable portably for the first time. Our sources say this is the closing announcement of the direct.
A few hours later it will be announced that Dark Souls Remastered is also coming to PS4, Xbox One and PC. These ports are being handled by a separate company from the Switch port, and will feature rebuilt lighting and SFX based on Dark Souls 3, as well as upscaled textures. One change we've been made aware of is that multiplayer will be expanded to support six concurrent players, which makes sense if the goal is to get Dark Souls' covenant system working a little more smoothly.
One of our sources indicates that Bandai Namco plans to bring all three Dark Souls games to Switch eventually, but the oft-rumoured 'trilogy' bundle is not how this will be happening – yet. The Dark Souls Remaster will be launching in May on all platforms.