Scarlet Sorcery

My take on this set: This set gives some more play to the keys, both on side of the enemies and the players. Key Charge is particularly nasty and one of the very few Surge cards in The Scarlet Keys. Thankfully Surge is not a huge part of this campaign at all, but this one card does pack a punch for sure. Bound in Red meanwhile makes the strongest enemy even stronger and turns them into a real pain to fight head on. By giving the players the option to depower the enemy back to normal by using up one of their own key charges, Bound in Red does manage to give a tough choice that i find interesting to think about. It’s one of those rare cards where the choice isn’t always all that obvious and i appreciate that a lot.
I frequently groan when drawing these cards because they are a pain to deal with, but that’s not necessarily a bad thing. It just means this is an impactful encounter set that does leave a mark on its deck. It also interacts with various other cards in interesting ways. I like it, but it’s probably not a coincidence that the two scenarios that are generally regarded as the most difficult of this campaign (Dead Heat and Shades) both have this set in it.

What it does: Bound in Red attaches to the Coterie member with the highest printed health and increases their fight, evade, damage and horror values by one. To get rid of Bound in Red, an investigator at any location can take an action and shift one of their keys from Stable to Unstable.

My take: Very often, the coterie member with the highest printed health is going to be one of the unique enemies, like the Beast in Crimson and Amaranth in their respective scenarios or one of the people you “haven’t seen the last of”.
Discarding the card is easy to do in principle since it doesn’t require a test, however it does require flipping a key which will vary in how much of a cost that is depending on whether you were planning on using it and/or how easy it is to flip back. It’s also an action, so it can trigger an attack of opportunity which would include the extra damage/horror from Bound in Red if the investigator is engaged to that enemy.
Since most of the unique enemies tend to have rather high fight/evade values, the +1 from this card only makes matter worse. As a result, this is usually a card that you can’t ignore and spending that action should be done early if the enemy is still concealed.
This card is particularly nasty in Dogs of War version 1, where it will bring up the Beast’s damage and horror to 3 each, enough to defeat a Key Locus on two players in one strike when the Beast patrols into its location.

Threat level: Mid to High. Sometimes not an immediate threat and it does come with a way to discard it. But it’s impactful and hard to ignore.

Dealing with it: The earlier you get this out of the way, the better. Unless the card happens to attach to a regular enemy that goes down in one hit, having this attached to something you intend on fighting can be a real issue. If your group only has one or two keys, the cost of having to spend one of them can sting, especially if you already used them. For example, if all you have is the Eye of Ravens and you used it earlier to pass some other treachery test, you’d have to first turn that back to Stable (which will draw an encounter card, basically giving this Surge) and then spend the key again. Obviously that’s a rather grim effect and at that point, just pushing through the extra fight/evade might become worth the effort. Meanwhile a team that has multiple keys and maybe even doesn’t necessarily need them or is easily able to switch them back and forth will find this treachery easy.

What it does: Key Charge makes each Coterie enemy use their keys, if available. The card surges, so this happens in addition to another encounter card.

My take: Another high variance card that will depend a lot on circumstances. Since it’s a Surge card that you just get as an addon to whatever regular card you are drawing, you aren’t ever going to be happy to see this treachery, but the actual effect can be all sorts of nasty things like having to draw another encounter card (effectively turning this into Overzealous… yikes) or having to discard random cards from hand or play. For the most part, these effects are going to hit everyone at the table, too.
If your luck is really rotten, then you will draw this with multiple enemy keys on the board. That is going to hurt, no matter what.

Threat level: High. A surge card with potentially high impact.

Dealing with it: Interacting with the card itself is sort of difficult and usually you’ll just have to weather the effects of the key(s) when it happens. As a Surge card, it even is awkward to cancel with cards like Ward of Protection as the Surge will still happen.
This card hurts most when you are already behind, when you had to concede keys to your enemies and might run into the possibility that you have two enemy keys on the board: One from whoever is the unique enemy of the scenario and one from a coterie member you “haven’t seen the last of”. As a result, that extra coterie member should be a priority to take out whenever Key Charge is part of the encounter deck just to take the key off the board. Of course, that’s not going to be easy to do with the key of the scenario specific enemy… after all defeating that one usually ends the scenario itself.