Diana Stanley's Blessed Magics

Diana is a little slow to set up, as a Mystic that starts with 1 and built around willpower. This deck loads up heavily on cards to delay or cancel threats until she's able to start pulling her weight, at which point she will happily go toe-to-toe with every enemy that shows up for the rest of the scenario. It's not unusual for her to spend the first turn or two drawing, getting resources, and playing cards, instead of contributing at all to progress - although she should do her best to throw out (and put under her own card) events to help protect her team while setting up.

Starting Deck Finetuning

The cards in the listed deck are a generic build where Diana focuses on combat and blessing, but splashes to handle a mix of other tasks when not in combat as well. Depending on the group, there's lots of room for shuffling cards around.

"Get behind me!" has an unusual niche use when another investigator has an enemy engaged with them that you wouldn't normally see: Diana can play out her whole turn (still focusing on setup) ignoring the enemy engaged on a friend, throw out "Get behind me" as a fast, and the other investigator can do whatever they want to take an attack of opportunity - the enemy only gets one attack of opportunity that is redirected to Diana and reduced in horror, letting Diana put "Get behind me" under herself during the investigator phase, and then play a Dodge during the enemy phase which can also be put under Diana, quickly ramping her into high willpower and the cards she needs for her engine. Depending on the group and campaign it may be worth putting in a second Get behind me, probably in place of Read the Signs, but it's often too niche to use effectively and ends up a dead card in hand if your teammates aren't regularly running into enemies that deal horror.

It's also worth considering seconds on Storm of Spirits or Shrivelling or Brand of Cthugha if your team wants you to focus further on fighting. If the rest of the team has more bless generation already, a second Rite of Sanctification may also be a good choice for the first few scenarios in place of absolution or book of psalms.

I don't know if Safeguard is worth picking up in this deck normally; there is definitely a good argument for it but it takes valuable resources usually needed to get other setup into play. If there is more support on the team to help you get that out early in scenarios (even if it's just blesses for a second Rite of Sanctification), or you expect the rest of the team to be very mobile and leaving you behind, it's probably worth getting, but I've usually found myself very pinched on resources and cards the first few turns and could deal with needing to spend an action to move every other turn or so.

Upgrades

Olive McBride and Spectral Razor are some of the first cards you will probably want to get, followed by Sacred Covenant. If you can get just 5 scenario experience, you can get both Olives(1+1), Sacred Covenant(3), and a Spectral Razor(free) with the discounts the permanents give you, which is the ideal goal.

After those you start considering what's needed for your team and situation overall. The second Spectral Razor upgrade makes the core combat synergy more reliable. Favor of the Sun is basically 3 guaranteed do-not-discards on your upgraded event spells. Ward of Protection is always a lifesaver from anywhere. Brand of Cthugha is good enough to consider a second one even - it's one of the few ways Diana can do her job reliably even before she gets set up and it's one of the best ways Diana can do her job. Prophetic is amazing economy and some skill boost when you can afford it - It's less helpful for teammates, but Prophetic can fairly cleanly replace Rite of Sanctification and maybe a Delve Too Deep. Grounded is maybe an alternative to Prophetic or you can get both as late campaign skill checks become more difficult - note you can sort of cheat Down the Rabbit Hole with Grounded by technically getting the level 1 version first and immediately upgrading it to level 3. Uncage the Soul can replay your Storm of Spirits for free which is how I mostly end up using it - in theory it's also great for recycling used up spells, or getting back a Spectral Razor that was unfortunate enough to whiff on symbols despite Olive's help, but usually you don't need that much combat endurance in a single scenario. There are plenty of other upgrades available too, if you find your guardian needs to do less-guardian type actions often - in particular Read the Signs with the deck's synergies can get a great number of clues if you're not busy fighting.

Gameplay

The first scenario does play differently, as you don't have access to many of the big synergies that star in the deck yet. Absolutely keep Brand of Cthugha, or Shrivelling if you don't have brand. If you do have one of those, an Ancestral Token is also very nice. Besides those, any canceling events are probably worth keeping besides Radiance. Olive McBride is nice to have but maybe not worth keeping in the first scenario's mulligan. You will likely need to keep getting resources throughout the scenario to pay for things.

After the first scenario, there is enough ignore effects in the deck that you usually don't need to start with more than 1 (again, not Radiance) and have reasonable luck for drawing into more. What's more important is Olive McBride, Prophetic, and any reusable attack - namely, not Storm of Spirits. It's harder to find a good hand where you immediately want an Ancestral Token though, more often you will want to mulligan that away, but if you are the only source of blesses in the group it may be worth keeping that or Book of Psalms in an opening hand. Unless you get an amazingly ideal hand though, you will still often spend a couple actions the first few turns drawing cards and getting resources to help set up. Remember to keep a resource free if you want to play a Dodge on the enemy phase - even though it nets 0 with Diana's ability, you still need 1 to play it.

The usual goals of setting up are, in approximate order:

1. Find Olive McBride. Play if you feel it's safe or see a need for her ability.
2. Find a repeatable attack card (Brand of Cthugha and Spectral Razor are ideal)
3. Get Prophetic in play (Ideally before playing spells, but don't be afraid to pay hard resources for your spells if you aren't finding this quickly)
4. Get ~4 cards underneath Diana (4 is sometimes better than 5, because of how it interacts with Sacred Covenant)
5. Get above assets in play if they aren't already
6. Get Ancestral Token in play

As long as your weaknesses aren't too scary (Deny Existence nicely neuters Terrible Secret), abusing Sacred Covenant to draw cards and get resources is usually worth it even if you will have to discard cards, and is the main reason you would want to stop at 4 cards under Diana (though, if you need to play a particularly nice card like Deny Existence that you definitely want to play again, it's probably worth gambling and putting it under Diana). Once you have Twilight Blade in play, going up to 5 cards under Diana is much more comfortable. Pretty much every is worth pulling cards back from Diana - the easier to replay, the better (Deny Existence, Ward of Radiance, Dodge, Ward of Protection, in some situations Read the Signs). Don't be afraid to take an attack of opportunity when you can cancel it and put the cancel under Diana - sometimes it's even the best way to prepare before making an important attack. Olive McBride is directly improving your odds on basically every situation you use her, from giving you decent odds of a chain of 's when the test is higher than your score, to virtually eliminating any chance of failure when you're doing 10+ skill attacks, so get her out early and never hesitate to use her for your most important actions.

Once she's set up, Diana can continue dishing out damage and protecting everyone from damage pretty much indefinitely. Olive McBride's ability to see 4 tokens at once cannot be overstated in its ability to make the upgraded Spectral Razor an almost guaranteed reuseable and autohit 2-3 damage a turn, as well more chances to hit which means more reusing events to nullify damage and threats - or if nasty treacheries show up and Ward of Radiance doesn't see a success in the first 4 tokens you can then exhaust Olive to get a few extra chances at a success. Prophetic allows you to play a Spectral Razor every turn without bleeding resources. Sacred Covenant keeps blesses around longer for the whole team and keeps Diana fueled in cards and resources, since ignoring at least one satisfies the reaction, and while the 'Place that card facedown beneath her' fails to happen since Sacred Covenant is a permanent, the draw and resource still goes through.

Diana wants to be focused on dealing with the monsters that appear, mostly leaving clues and other weird skill checks to other investigators. Ancestral Token is a great reward for the whole team as Diana chews through enemies, and Brand of Cthugha and Spectral Razor make it very safe to attack enemies engaged with allies without needing to spend actions on engaging. When the occasional nasty Forced effect on an Investigate shows up, you may want to handle it with Read the Signs personally instead of having the dedicated clue person investigator suffer its effect, since such effects are actually a benefit here - they allow Diana to put Read the Signs under her card.

As long as the card can be tracked (i.e., not shuffled into your deck), you can still grab it from other locations as well. This lets you pull a few especially sneaky things such as using Heavy Furs or Olive McBride during a skill test, having them discarded due to damage, and then putting them from discard to under Diana with her ability. Olive is valuable enough for many of the synergies in this deck to try to keep in play unless you have another one in hand already though. It's rare to come up, but you can also do the reverse with Read the Signs - After doing an Investigate that ignores an effect on the location, you can put it under Diana for +1 resource and card. Then at the end of your turn, Read the Signs comes back from under Diana to your hand.