Christmas is a holiday event taking place in December each year. The roleplay in the Kaelicious social group got the most popular during its first Christmas-event by Vengeancekael named "Santa's Workshop" in 2012. In 2013 the second Christmas-event was arranged by Bernkastel who named it "The Red Christmas", which was also the event that returned the original Kaelicious universe to the on-going roleplay.

In both the Kaelicious- and the Hollideus universes, the Christmas holiday is closely related to the Christmas Elven civilization of the Valley of Christmas, who elects their leader, the Idol of Christmas, with the magical power of the Christmas Gear the first of December, so that the Idol can use the power to bring out presents to all of the nice people of the planet on the climax of the holiday, Christmas Eve which takes place the 24th of December.

However, the idea behind Christmas, as well as the powers associated with it, automatically brings great enemies with it. In 2012 the Mad King and his demon people attacked the Christmas Elves simply because they were disgusted by the idea of Christmas. The Shadow Cult is also known to dislike the holiday, and have ideas of changing it into a totally new holiday event called Rlyehmas

Due to the second Kaelicious-event being based on the Christmas-holiday, the second novel in the Hollideus Project is going to be based on that event as well, with the title "Hollideus II: The Christmas Conflict".