The Advent Monsters is a new sub-category of monsters introduced by LHK, and it is the first of the innovations LHK made in 2015. They have strengthened effects which are unlocked only if it is played in a specific month(s) stated on the card's text. The maximum number of months they must be mentioned on the card's text is 3, and at least 2 of them must be consecutive months (e.g. May, June and September is okay, while April, July and December is not). It is spearheaded by the "Zodiac" archetype. The Summon is treated as an Advent Summon. It is similar to the Overlimits and Geminis, by the fact that the monster must be on the field already to be Summoned, then it gains that effect if the month is the one stated in the text.