Marion is very broad in terms of ways to build her deck, so in writing this review I'll provide an overview rather than the impossible task of summarising ever possible deck style you can make with her. I've broken this down into a couple of sections, and provided a couple of exemplar decks around specific concepts.

Features:

• A good 2 3 4 3 statline, which encourages some flexing - especially with Determined which provides recurable boosts on events.
• Her ability gives innate card draw for playing an event, and allows you to play a second event as an extra action. This cements any deck you will play with Marion as an event deck.
• She has one fewer hand slot, which can be considered a feature and not a bug if using this to displace one-handed assets with limited uses (e.g. guns). Stubborn Detective as we all know can magically make you regrow an arm...
• She is a Drifter and Entrepreneur, so Double Down, Bound for the Horizon, True Awakening and Nose to the Grindstone are available as XP purchases.
• She has access, providing five level 0 cards. This can do a lot of heavy lifting - as Marion's weakness "I'll do it myself" makes you discard events and Winging It, Improvised Weapon, A Glimmer of Hope and Impromptu Barrier are all events which can be played from your discard pile.

• She has access to 0-2 events of a chosen Trait from either Fortune, Gambit or Improvised. You can search these using "k:[chosen trait] t:event p<3". Some of these of interest are below (with events I consider especially useful in bold, and there's hyperlinks to the relevant searches by clicking on the Trait name):

  • Fortune: "Look what I found!", A Glimmer of Hope or A Glimmer of Hope ••, Fortuitous Discovery, Good Weather, Hot Streak ••, Keep Faith, Lucky!, Oops! ••, Scrounge for Supplies

  • Gambit: Act of Desperation, Bank Job, Honed Instinct, Kicking the Hornet's Nest, Swift Reflexes

  • Improvised: "Where's the party?", Improvised Weapon or Improvised Weapon ••, Makeshift Trap, Pushed to the Limit, Snare Trap, Winging It

Deckbuilding considerations:

• Combat: Guardians have a lot of great fight action events, and Marion rewards you for using them. In terms of level 0 fight events to consider there's One-Two Punch, Monster Slayer, Toe to Toe, Clean Them Out, Improvised Weapon, Act of Desperation, Pushed to the Limit and "Get over here!". For higher XP fight events there's One-Two Punch •••••, Fang of Tyr'thrha, Gang Up, Radiant Smite, Improvised Weapon •• and Sweeping Kick. There's other events which allow you to fight or deal more damage, such as Dynamite Blast, Quick Shot, Galvanize and Hunter's Mark.

• Flex: With a useable of 3, events which allow you to investigate can be a great help. Winging It is a strong contender here because it can be played from your discard pile. Fortuitous Discovery is also nice as you don't mind too much having one copy discarded (for example, if you need fodder for "I'll do it myself"). If you take Fortune or Improvised as your chosen trait, this can exempt Fortuitous Discovery or Winging It respectively from your five level 0 cards. Access to the likes of Matchbox also strengthen capability to flex, as can A Glimmer of Hope or Good Weather. Note that even an event which doesn't provide an additional clue is fine (such as Winging It from your hand, or your first Fortuitous Discovery) as it's more about having events on hand which allow you to take an extra action of the type you're interested in. Cards like Scene of the Crime, Evidence!, Breach the Door, Guided by Faith and/or Kicking the Hornet's Nest (if taking the Gambit Trait) can further help clue-finding efforts, as can allies such as Field Agent or Grete Wagner.

• Event manipulation: There's a couple of noteworthy cards which allow you to manipulate events: Stick to the Plan and Book of War. Stick to the Plan gives you ring-fenced events to play and activate Marion's ability with, while Book of War allows you to recur Tactic events round after round (especially useful if you have a high XP event in your deck). For an example of a deck using both of these, please see the excellent One-Punch Marion deck by Valentin1331.

• One-handedness: As mentioned earlier, having one hand slot in some ways can be considered an exploitable feature and not a bug by giving you an easy means to discard assets with uses. The new Remington Model 1858 •••• allows you to take an action with it when it's discarded (i.e. displaced from your single hand slot), so by having two of these it's easy to squeeze in additional fight actions. The really cool Marion Takes a Gunbit deck by Providence shows how to do this style of deck well. In addition, assets which use less used slots (Brand of Cthugha) or are slotless (Mk 1 Grenades) may also be useful on Marion if you want to use the handslot for something useful like Blessed Blade ••••. The deck Quick Rigging Marion! by the infamous StartWithTheName is a great showcase of these ideas.

• Other useful events: In addition to fight and investigate events, it's worth mentioning several others. True Awakening is a great catch-all event which can provide clues, healing and/or card draw - flexing to exactly what you need at the time. As highlighted and depending on your chosen Trait, Marion can have access to resource generators like Bank Job and Hot Streak •• which can make you flush with cash, in addition to Guardian staples like Stand Together •••. For healing, there's the likes of Emergency Aid, Short Rest, Second Wind and Ready for Anything. Of particular note is Hallowed Mirror and Hallowed Mirror •••, with the latter providing an endless supply of healing which can be paired to allies that take damage or horror regularly, such as Grete Wagner, Beat Cop •• or Field Agent. For a Hallowed Mirror focused deck, my own Field Agents on a Boat! is a good a example (I think!) to show that capability.

I hope the review has been useful in showcasing what you can do with Marion. In particular, I think there's been so many good and distinct Marion decks already that there's a lot of inspiration to draw on! Let me know your thoughts.

I just want to add that "fast" event cards, which can be played under any circumstances, work wonders for Marion. They allow her to combo other events in any flexible timings without spending actions. Notable mentions include "Get behind me!", Tempt Fate, and Trusted (attached to an ally). This strategy lets you chain actions together to achieve meaningful outcomes. I recommend packing some cheap, condition-less "fast" event cards in her deck.