Today is the last day to play the Nioh Alpha Demo. Once it goes down, we won't see it again for a while, and this is your only chance to earn the Mark of the Conqueror, which will provide an exclusive bonus when the full game is released. We don't know what that bonus may be, but why miss out?
So if you haven't gotten your Mark yet, or just want to enjoy the awesome combat again before it goes away for a while, now's the time to do it. Personally, I'm sad to see it go, and had some good things to say in my impressions of the demo. Koei Tecmo and Team Ninja may be onto something special here.