The next set of 4 is a whole new card type which I came up with some time ago: Support cards. These cards are played along with a host card, which can be any other card that you play. That means you can play a Support card with an Action, a Treasure, or even another Support card. They each alter or interact with the host card in different ways.
So, I really like the concept of Support cards, but I have some questions about how the mechanic works. First, what is the timing? Do you resolve the Support card or the host card first?
Chambermaid
Support
When you play this, trash a card from your hand. When you discard this from play, trash the host card.
Inscription
Support
Add 1 to all numbers on the host card.
From Inscription I would guess that you would have to resolve the Support card first (after all, once the host card is resolved you can't go back and add 1 to the numbers). But does that mean that if you played Chambermaid on a Ruined Library you first trash a card then resolve RL (drawing a card)? That seems counterintuitive.
They will be attached to the host card until it goes back into your discard pile, so if you trash the host card or set it aside, the Support card gets trashed or set aside as well.
What if the card goes back onto your deck (e.g. with Herbalist or Scheme). Does the Support follow it? If so, is the Support card still "attached" to the card? What if you draw one of those cards but not the other (if you put 4 more cards onto the deck after)?
How would this work with Fortress? If you trash it from play (with Improve or Bonfire) does the Support stay in the trash or follow Fortress back to your hand? And, again, is it still "attached" to Fortress, or can it be played on a Night card? What if you trash a different Action card from play, then gain that Action back using Lurker. Is the Support still attached? What if you gain the Support using Graverobber or Rogue? Does the card it's attached to come with it?
What about when cards return to their piles? If you play a Support on a Horse, does the Support card do back to it's own pile or to the Horse pile (or neither)?