Mystery Contract (秘契約 ; hi-keiyaku) is a family introduced in BS61, possessed exclusively by the Contract card The PartnerBug Gataru and its subsequent cards with Contract Advent. The family is a representation to the contract, which is a part of the World Destruction Contract, which Gataru made with an unrevealed character in the lore, and since all the Green cards with Contract Advent are technically a variant of Gataru's power, they have the Mystery Contract family as well. All cards in this family are also part of the bigger Jade Thunder family.
Play Style[]
As currently all cards in this family are either a Contract card or a Green card with Contract Advent, the deck highly revolves around the Advent mechanic. As part of the new series after the age of Rebirth cards, it also plays around high numbers of counters to differentiate themselves from the previous cards. Cards in this family are also always paired with the Jade Thunder family, often along with a tertiary family which is mostly irrelevant to the play style of the deck, so the play style may overlap with other Jade Thunder family cards. The Mystery Contract focuses specifically on summoning Spirits via effects, usually via High Speed, and returning them to hand to summon them again, forming a swarm attack tactic.
Being a swarm deck, there is hardly a division of early game, mid-game, and end game stages for the play style. Often the key finisher of the deck, The ShellBuzzSorceryMaster Elder-Gataru, is not even needed to finish a game. A lot of the Spirit cards with High Speed are also low cost, plus they can core boost on summon, so the player can begin their assault as early as turn 1 starting second. There are also Eclair-Tiger from BS60 and The Grün∴Baum DemonKing Zanardite from BS61, which serve as backup in case Spirits on the field are getting wiped out.
As the deck is not closely tied to the Mystery Contract family or the Jade Thunder family, the player is always welcomed to add external supports to give the deck more firepower. The usual picks include The EighthMachBraver Sonicwasp-Ace (which can banish trash and return itself to hand), The SecondWhiteKnight Alpine-Bit (which can recycle cores), and the Revival version of The BlackInsectDemonLord Diabolica-Mantis (which can serve as a defence card, but also act as additional offence).
Like any typical Green decks, the deck often lacks draw power, so if the player cannot break through the opponent's defence before their own hand resources run out, they are at a risk of an unstoppable counterattack.
