The Cultist and The Council's Chosen

The core concept of this deck is to fill two roles: enemy management, and team support. The deck is designed for use in high player count games - preferably 4, but could probably also function well in a 3 player game.

Enemy Management

Similar to the "Eldritch Knight" deck posted previously, this deck does not focus on ramping up Diana's willpower, but uses Diana's 3 combat and guardian access to handle enemies. This gives her more early game efficiency than the standard mystic route and allows her to save her powerful canceling events for when they have maximum impact, instead of using them quickly and less effectively to ramp her willpower stat. She still wants to pack plenty of cancels, since the extra card draws and resource gains are strong benefits.

Team Support

With Ikiaq, protective incantations, and hallowed mirror, Diana brings a strong support package for your teammates. These cards are the main reason this deck is intended for higher player counts, since they bring more value with more teammates. Ikiaq is a core component of the deck, protecting you and your team from weaknesses. In the early game Ikiaq's stat boosts protect you a bit from the encounter deck and even possibly allow you to do a bit of investigating. However, the deck is designed to work well without high willpower or intellect values, so you can bury weaknesses with abandon, unperturbed by the stat debuffs. Safeguard is included in the deck to keep you alongside as many teammates as possible, to better protect them from weaknesses and enemies. Since you have no need for fighting or investigation spells, your empty arcane slots offer a strong support option: protective incantation. These can be very high impact in high player count games, saving all your teammates cards and resources and increasing the success rate of their actions. A couple of resource cards and Diana's innate resource generation should be enough to pay for this. Recall the future works well with the incantations, since the protective spells narrow the list of tokens that can cause your tests to fail. Hallowed mirror, dodge, and later, ward (2), fool me once, and counterspell round out a powerful team assist suite.

Future upgrades

Fool me once, ward (2), and counterspell are good team support cards and cancels. Fool me once is especially strong with Diana, as you can loop it using her twilight blade. I've had worse is a strong cancel card, and offers resource generation to fund incantations. Beat cop (2) (with charisma) and timeworn brand boost your fighting efficiency.

Other options

Survival knife (2) is a solid option for this deck. You're already packing dodge, which works well with this knife. If you add this in, I'd consider switching hallowed mirror for 1x riot whistle and you could switch recall the future with well prepared, since survival knife has 2 combat icons.

Empower self (stamina and alacrity) could be added for combat boost and added evasion ability. These synergize with well prepared. Drawn to the flame and/ or Scene of the crime can be swapped in as solid clue getting options.

Additionally, you could run a similar deck with Charlie Kane acting as a fighter and using Ikiaq to support teammates.

This deck is not game-breaking, but it is strong and fun to play. I certainly recommend it, especially if you enjoy picking up a supportive role.