"Dark Contract", known as "Contract" (
The "Dark Contract" cards deal damage to their controller each Standby Phases of their turn, in exchange for other advantageous effects. They are supported by some "D/D" monsters and have great synergy with them, helping the "D/Ds" to perform all kinds of summons without losing much Hand Advantage. They are also supported by other cards used by Declan, such as "Contract Laundering", which allows the player to abuse the advantageous effects of the "Dark Contracts" cards while getting rid of them before their "payment" kicks in. As a bonus, the trap even "refunds" the player with an extra draw and 1000 LP for each "Dark Contract" destroyed, removing almost all conceivable disadvantage the "Dark Contract" payments could impose.
Apart from "Contract Laundering" other cards can be used to combo with the toll from the "Dark Contracts" without destroying them. For example "D/D/D Rebel King Leonidas" can Special Summon itself upon its user taking effect damage as the "Dark Contracts" inflict, while providing a solid body of 2600 ATK and restoring the lost LP, he also prevents further effect damage, allowing the Dark Contracts to be used as much as one wants without consequences, provided "Leonidas" is alive.
An even more impressive play involves "D/D/D Oracle King d'Arc" which can convert any effect damage into restoring, thus being able to amass an impressive amount of LP each turn, being able to reverse the negative effect of the "Dark Contracts" that can result in large values of LP through cumulative gain. Furthermore due to converting the effect damage into LP, even if "d'Arc" and "Leonidas" are together, "Leonidas" won't interfere with "d'Arc" enabling the LP gain to continue. Through this method, the "Dark Contracts" generate several advantages at no downside.
If neither "d'Arc" or "Leonidas" are available and in a desperate need to conserve LP one can also employ other less sophisticated methods, for example using "Dark Contract with the Witch" to destroy itself or other "Dark Contracts" before the damage takes place.