The priest class has me a little conflicted. The other three classes serve good, generic roles that can be easily adapted to a variety of different character types. However, the role of "priest" is much more specific and comes with a lot of baggage. At it's heart of course it's actually a very flexible archetype: the 'support' character. This could be a priest, a bard, an inspirational warlord. But the "priest" is so deeply ingrained as the final member of the "big 4" of the classic dungeon crawling group and it has so much history. Not to mention "supporter" makes a terrible name for a class. Leader could work but that still has a lot of baggage.
For now, I'll stick with the idea that what I'm describing is a priest of generic "good" gods. In reality it has a much closer resemblance to a paladin. Since the Mage is the primary magic user they're the ones who'll get the flashy powers. The most obvious of the Priest's Tricks is Support which covers healing as well as the ability to enhance the abilities of others. I'm still a little torn on the other one. My first thought was "smiting" which would cover things like blasting evil and all that...but since part of the goal is to build a very generic set of abilities I don't want to get into too many circumstantial situations. Instead I think I'll make their second tree Miracles. Like a Mage's spells Miracles focus on the ability to perform abilities not covered by normal actions, but they're more focused and less flexible...but often more powerful. Lets see how it works out. Unless specifically noted a priest's powers cannot be maintained like a Mage's
*Holy Warrior: The priest is exceptionally good at battling the enemies of their deity. For most "good" gods this means they have an advantage against beings of supernatural evil such as demons or the undead. Different settings or dieties may alter these definitions slightly. For instance in a setting where there are few supernatural foes your Priest may receive a bonus against followers of enemy gods. Either way, if the priest succeeds at an action against their god's foe then they increase the margin of success by 2.
*Shield of Faith: Each religion has a few basic tenets which should be worked out by the GM and the player. If the priest violates these tenets willfully then they should lose their holy abilities until they atone. However, the priest receives a +2 to the Card Value of any actions made to resist being forced or coerced into breaking the rules of their faith.
-Prayer: Before he sleeps for the night a priest may pray to their deity for some specific situation ("strengthen my arm against my orcish foes" or "give me courage when I face the dragon") and set aside a Hearts card. At any time the next day when faced with an appropriate situation the priest may use the card for an action and treat it as whatever suit is appropriate for the situation.
+Guidance: At any time when the priest or one of his allies plays a card which fails the priest may discard a Hearts card in order to allow them to play again, opposed by the same Card Value as before. the original card is still discarded.
-Command: As an action against a target (Hearts vs Hearts) you may command them to perform a single action that would not normally require playing a card (dropping an object, moving, not moving, etc) and would not result in direct harm to the victim. The target may act normally after their next action.
+Aid: Play a Hearts card and your or an ally you can reach may take a number of cards equal to the Card Value from their discard pile and put them at the bottom of their deck.
-Sanctuary: With about 15 minutes of work or prayer and you can consecrate an area the size of a large room and ensure that no hostile beings may enter or attack anyone within. Anyone within the zone of safety who attacks or otherwise breaks the "truce" will ruin the protection. You must discard at least one card, the protective sanctuary lasts for one hour for every card discarded.
+Boon: Pick a suit, so long as you are conscious any allies within Close range receive a +1 to the Card Value of actions played using the suit. You can change the chosen suit by spending an hour or so praying/meditating.
-Divine Retribution: Play a Hearts Card. For the rest of the Scene
whenever you make a defensive roll using Hearts cards then the attacker
suffers an immediate "counterattack" using the Card Value of the card
used to activate this Trick.
+Rejuvination: Discard a card to allow you or an ally to swap a card from their hand with their discard pile. Each additional card allows an another target to be affected.
-Get Ye Back!: By discarding a Hearts card you
may make an attack against all foes who are In Your Face. Discarding two
will increase the distance to Close.
+Stand Strong: Any time an you or an ally in Close range is damaged you may discard a card to reduce the damage suffered by 2 (to a minimum of 1).
-Holy Weapon: Play a Hearts and a Club card to
summon a floating weapon. Treat this as an NPC with a Clubs and Hearts
rating equal to the Card Value of the cards you played -1 and a
Spades/Diamonds rating of 1. You may play cards for the weapon in the
same way the DM plays cards for NPCs. It vanishes if successfully
damaged or at the end of the scene.
+Never Give Up: Any time you or an ally within close Range are taking an action that would be Difficult you may discard a card to reduce the Difficulty by one step.
-Smite: If you discard a Hearts and Diamonds card you can make an attack (as a separate card action) to call down your god's wrath in the form of a column of fire, lightning or holy power. This is a ranged attack which affects everyone Close range of the target, and will inflict double the normal damage if successful.
+Good Fortune: After drawing your first hand from a Deck (at the start of an adventure or after a recovery) you can set aside up to five cards, face up. During the course of an adventure you or an ally may discard a card to use any of these cards as part of an action or to power a Trick.
-Summon Servant: You may call upon a divine servant. To do this you must play a single card of each Suit. These cards become the servant's attributes (it cannot have any attributes above a 10, regardless of Card Value). You may play cards for the servant the same way the GM plays cards for NPCs. The servant will remain for one Scene and will carry out it's deity's wishes, so it is under GM control and may or may not do exactly what you expect
+Healing Hands: Discard a Hearts card and you or a touched ally are cleansed of any diseases, poisons, curses, or similar negative effects. They may also (if they wish) shuffle their current hand back into their deck and draw a new hand.
-Wrath: Discard a Hearts, Clubs, and Diamonds card to invoke a powerful curse on a target, which cannot be resisted. The target suffers pain, blindness and spasms, making any actions Difficult. This curse can only be removed by another priest of equal power or similar divine intervention.
+Savior: By discarding a Hearts card you can reduce damage inflicted to you or an ally to 1.
-Avatar: Discard your entire hand to assume the form of your diety's avatar. While wielding the power of the avatar all Card Values are doubled (before counting any bonuses). You may keep channeling this power so long as you can discard a Hearts card at the start of your turn. Once you return to normal you must discard your entire hand again.
+Miraculous Recovery: The target immediately shuffles their hand and discard pile back into their deck. This can even bring a character back from unconsciousness or death so long as it hasn't been longer than a Scene since they died. However, until they have time to take a normal recovery they must discard an extra card every time they take an action or reaction. This power cannot be used more than once per adventure on a particular target.