It's more or less a Resourceful but for spells. Being , it has a game attached to it. I think this is mostly a chaos bag Mystic kind of card, most likely limited to Jacqueline, but fun if you like gambling. Most Mystics will prefer to take Fearless, Guts (2), or maybe Defiance for a willpower boost.

This is a flavorful card, but I'm not sure how effective it is outside of Jacqueline or another chaos bag manipulation Mystic. It's also of less use in Solo, since you can't parcel out the cards to the investigators best suited to withstand them, although knowing what the next 4 Mythos Phases are going to spit out isn't nothing (always assuming the Act or Agenda doesn't reshuffle the Encounter Deck before you get to the 4th Round).

It's most similar to First Watch, with -1 cost, requires an action, has a "bad stuff token" test, and always looks at 4 cards. In 4-player, First Watch is much better, in 2-player, Parallel Fates lets you pick between investigators for 2 turns, so it probably edges the card out.

Gloria Goldberg might like this, since it synergies with her ability, although she'll need chaos bag support to make it really work. All in all, this might have a few too many moving pieces to be a mainstay, and I'd be happier if it was Fast or didn't have the token pull, but maybe future cards will make it more reliable.

Pretty much everything that one can say for the Level-0 Version, but more so. How does it stack up to Mists of R'lyeh (4)?

• Costs 1 more XP
• Costs 1 more resource
• Has 2 fewer charges
• Doesn't give you a free move
• Does 2 points of damage
• Might cost an extra 2 resources if you draw an , +1, or 0

This is looking like a less attractive upgrade, especially since a bad draw with Mists (4) still only costs you 1 card. Alternatively, if you compare it to Ineffable Truth (3), you are getting a +1 and +1 damage for a cost of 2 XP and the risk of an extra resource lost on an unfortunate token pull. I suspect it will take a very specific deck to want to upgrade beyond the 3-level version of the card. I guess Meat Cleaver Agnes can use this to do 8 damage to an enemy in 1 turn, leaving it exhausted at the end, but Agnes has a lot of ways to hand out hurt.

It also doesn't compare all that well to the higher-level versions of Mists, although you probably want to look at Ruduen's comments on the "good token" vs "bad token" suite in the Azure Flame review.

Obviously, 2x Arcane Research mitigates some of the extra XP issues, but you could still be spending that XP on cards that provide a bit more punch for the cost.

TL;DR? Level-0 is fine, but, if you are going to upgrade, you might want to stop at the 3 XP version.

Normally, I'd would entertain the idea of having a chance to not exile a card, especially if it's determined by a moderate difficulty test of a skill that many investigators in this class excel in, and also gain a 1 resource discount for 1 additional XP.

But the very same pack that introduces this card also contains a card that lets you return its cheaper variant back to your deck for FREE in between scenarios. Both copies, potentially. Understandably, you might not have Unspeakable Oath, or maybe, you really don't want to chance exiling your Test of Will. This pack gives you an even CHEAPER alternative with the exact same effect. The only thing that this card affords you over its Lvl 0 version is that the effect is guaranteed to happen in Lvl 2, but then you have to pass the exact same test in order to keep it from being exiled. If you weren't confident enough in passing that test to settle for the Lvl. 0 version, what makes you think that you can salvage the Lvl 2? In that case, you're just flushing an extra XP down the drain; I'd rather take my chances on the Lvl 0.

The biggest benefit this card is supposed to give you is saving your XP from having to dump it into upkeeping its exiles, and you know what, if you just bought 1 copy for the fun of it and wanted to see how far you could get without losing it, then sure, this card obviously has more sustainability over time than Lvl 1. But if you're including this in an exile deck or planning on buying 2 of these, just use Lvl 0 for lower difficulties and Lvl 1 + Deja Vu for higher difficulties. This card really has no place in your deck given the alternatives. If you don't have Unbreakable Oath, just pretend these cards are Lvl 1 problem solved :)

TL;DR: Think of the key as a late-mission MP support Event, not an Asset. It competes with no slots, and you don't have to play it until/unless it's needed. If 3R and 1 action to trivialize an entire 3+ Shroud 8+ Clue location for EVERYBODY in your party seems worth it, then it doesn't matter when you draw your one copy- you'll always be happy to see it.

+++

I recently completed a 3P Carcosa as Tony Morgan; the key here was a late upgrade in the "eh why not" vein after getting all his other needed upgrades. It ended up being a relief to see on each remaining mission.

Left me wondering why it never really got much in the way of reviews, but I think I can see why- it looks deceptively cumbersome. 3R to play, 2 actions to place & recover, only 1 per deck, Lockpicks exist, etc. But here's the thing: in 3-4 player MP, all of these become unimportant... a single use of the key will pay for itself.

• Fast. No need to play it til you need it, and ultimately costs only 1 action to place it at a destination.
• NO SLOT. Did you notice that? Some assume the key is an Accessory or Hand item at a glance, and thus in competition.
• Item. You can tutor it with Backpack, which many Rogues enjoy running.
• You likely want it late. High-shroud spots often reveal near end of mission. This reduces the 1-per-deck risk.
• Scales hugely in MP.

That last one's the biggy. It's rare that a campaign doesn't have at least one location with 3+ shroud and 2+/Investigator clues. In SP you can clear that with an event or skills. In 4P though, the Skeleton Key becomes an 8-charge Flashlight that your whole party can use in addition to any other investigation skills they have.

If you can get the key to work on 1 hard room in a mission in 3-4 player MP, it's a terrific and reliable value. The uninstall/reinstall effect is neat, but distracts from the fact that it should pay for itself with a single use.

(FUN FACT: Preston & Dexter & Sefina aside, everyone who can take the Key has 3+ base INT, and is thus themselves now investigating at a minimum of +2 after using it.)

(edited to add Sefina to sub-3 INT investigators, thanks to all who noted this in comments!)