Alright, possibly this mechanic is just on my mind because I'm getting married in a month, but let's do it!
I am introducing a new keyword:
combine.
You can be instructed to combine any number of cards. To do so, you set them aside together, in order, with some numbered token, and you take the corresponding card from the combinations pile (not in the supply) and put it in your discard pile:
The Combination card gets all types that are on any of the cards set aside with its numbered token. When you play it, you execute all on-play instructions of the set-aside cards in order. That's it! Effectively, all the cards you combine become a single card!
Here is a simple example of what a card using the keyword might look like:
Some additional clarifications:
- the cost of the Combination card is the sum of all costs of the combined cards, including Debt or Potions
- the name of the Combination card is the string "[first_card_name] + [second_card_name] + ...". Thus, two Combination cards are considered to have the same name if and only if they are made up of the same cards in the same order (the +s are in the string so that the new name doesn't accidentally turn out to the name of an existing card)
- there are 30 numbered Combination cards by default, and if there is no Combination card left, the setting aside fails. You may specify a different number of Combination cards for your submission though.
- the set-aside cards are not returned to the deck at the end of the game. However, the Combination card is worth any VP of a card it is made up of.
- any when-gain, when-buy or when-trash effects of the combined cards are ignored for the Combination. Other below-the-line effects (while in play, Reactions etc.) carry over to the Combination.
- cost reduction lowers the cost of a Combination by 1, not 1 times the number of cards it is made up of.
Good luck!