XFLAG and Mixi opened a mysterious countdown page for the Monster Strike smartphone game in Japan. If you visit the page you can see that less than 19 hours a new mysterious gift box going to be opened on the website with a special gift!
We will find it out on December 28, 2016 at 15:00 (local Japan time).

Until that, play with the game and claim your Xmass gifts!
The promotion website can be found in here: http://www.monster-strike.com/promotion/winter2016/