The 2015 Winter Mariolympics and also commonly known as Winter 2015, marked the second Mariolympic games as well as the first Winter Mariolympics.
The Winter Mariolympics saw the return of the: Modern Platforming, Sports, Mario Party, Retro Platforming, Mario Kart, and Super Smash Bros categories. Due to the winter theme, the "Mario Open Tour" was not present. A new addition to the Mariolympics was the inclusion of "Wildcard Events." Due to the short amount of time available for registration, a lot of potential participants were unable to take part. So to alleviate this, the inclusion of "Wildcard Events" were introduced to allow un-registered participants to take part without affecting the overall medal count. You can see a full list of events in the 2015 Winter Mariolympics HERE.
You can see a full list of all participants HERE
Due to the Winter Mariolympics' theme of Winter, the Kingdoms of Sarasaland and The Void, were unable to make a return from the Spring 2015 Mariolympics. With these two spots open, the Kingdoms of the Secret Society of the X-Nauts as well as Dream's Deep, were elected to fill these positions.
You can see the full list of Medal Winners HERE!