The core idea of this build is to harness the power of several multiplication effects—[Double], [Triple], [Quad], [Sneak Attack] and [Sliver]. These effects stack perfectly, resulting in a total damage factor of 2x3x4x3x6=432, for example. The initial setup for the character is shown below. Some skill sets are disabled to narrow down the card pool.

1. [Fay Seelie] Species: Grants access to effortless [Double] and [Sneak Attack] multipliers through [Fay Luck].
2. [Canticum Noctem] Organization: Provides [Sneak Attack], [Triple], and [Quad] multipliers through certain cards.
3. [Charlatan] Class: Chosen because it can disable enemies' sneak attack immunity through the perk [Notoriety] (although not strictly required for this build) and reduce the [Discard] effect through the perk [Mental Defense I]. For better retribution generation, you can choose [Shadow Elf] and [Thespian] under the performer category instead.
4. Background [Fortune Teller]: Considered the strongest background in my opinion, as it not only provides access to the [Arcana] card pool but also generates massive retribution/defend stacks through its ripple effect. The need for massive retribution generation will be discussed later.

You can find descriptions for all cards and effects in the Player's Handbook and Rulebook, available from the front page of the game.

Note that the late game strategy differs significantly from the early game strategy. During the early game, the easiest approach for this character is to utilize [Mark] from the [Marksman] card pool, which can vastly boost damage output. You can also use [Sneak Attack] from [Fay Luck] in combination with concealment from the discard effect of [Astral Leap] to deal huge damage.

Remember to reserve synergies for high-damage cards that do not ignore them; cards that consume synergies will also break [strain]. An example deck at level 5 is shown below.

For a deck to function effectively, the character needs to draw enough cards. [Lucid Dream] is particularly powerful in the early game, as it not only replenishes your hand quickly but also enables the use of many high-cost cards by recovering your AP. Other offensive cards are chosen for their [Draw] effects. To quickly acquire these cards, consider selling useless ones to the shop and using the funds to purchase useful ones. The shop refreshes its card selection each time you restart the game.

A good gear set is shown below. The main and off-hand weapons are chosen for their draw effects. The [Renegade's Leather Cloak] is used because it provides concealment, which is necessary to enable [Sneak Attack].

The recommended skill points and perks until level 5 are shown below. After level 5, you ONLY need to level up the [Witchcraft] and [Arcana] skills, as other skills and attributes do not significantly impact this build beyond the levels indicated in the figure below. (During the late game, you will need to level up the [Perform] skill to level 4, which will be discussed later.) Also, remember to check the rewards from the progression options, as some rewards are crucial to this build.

Regarding perks, they can provide higher [Mark] stacks and reduce your strain, both of which are very useful.


An example of a battle in the early game is shown below.
https://youtu.be/FNHEM14eheU

For the mid-game strategy, it is very similar to the early game strategy. Some important perks and cards are shown below.

1. [Queen of Cups]: This card can provide multiple stun stacks to different enemies and is far more powerful than single-target effect cards.
2. [Melcha of Grunwell]: Selected for the same reason, this card should be cast only at the end of the turn due to its [Coven] attribute.

Regarding perks, certain perks shown in the picture below can provide more concentrations and decrease [Strain], both of which are very useful.

Now, we've reached the most intriguing part of this build: how to deal 200,000 AOE damage. This late-game strategy relies on accessing key cards, which become available at level 8. Additionally, a crucial perk that grants [Retribution +8] to all actions is obtainable only as a progression reward after defeating 750 enemies. The basic idea of the late game strategy is shown below.
Achieving high damage requires two key elements: high base damage and a strong damage multiplier.

1. Building Base Damage: Typically, play or discard synergy-less cards (those that ignore synergy) with synergy effects to accumulate base damage and multipliers for a significant final blow from a card that consumes all synergies. [Wrath], acquired from the discard effect of [Knight of Wands], provides substantial base damage when paired with high retribution stacks. [Fortune Teller], empowered by [Retribution +8] from a progression reward and [Retribution +3] from the perk [Heightened Reflexes], facilitates massive retribution generation, contributing to high base damage. You can use the discard effect [Envy] from [Queen of Pentacles] as an alternative reliable damage source, where the damage depends on the HP you lost instead of retribution.

2. Multiplication Effects: [Fay Luck], [Phase], and [Vision] offer high damage multipliers by combining different effects. Note that while [Sneak Attack] can stack infinitely, effects like [Double], [Triple], or [Quad] can stack only up to 100%.

3. AOE Damage Mechanism: To achieve high AOE damage, the card that consumes all synergy effects must inherently possess AOE damage. [Eerie Melody], as the easiest available AOE damage card ([Perform] level 4), is used for this purpose, but its AOE damage alone cannot inherit the high base damage from [Wrath]. A unique in-game mechanism discovered in this build allows an AOE damage card to inherit high base damage from synergy effects: when affected by both [Imbue] and additional damage from synergy effects, half of the total damage, including additional damage from synergies, becomes AOE damage. The accessory [Celestial Fragment] effectively fulfills this requirement by providing [Imbue] and [Draw 1] effortlessly.

4. Regarding the high damage shown in the picture, the calculation is demonstrated below as an example:
1104 (Wrath) x 2 (Double) x 39 (Sneak Attack) x 4 (Quad) = 344,448.
This damage will be dealt directly to the target, and half of this total damage, 172,224, will be converted to light/dark AOE damage to all other enemies due to the [Imbue] effect from the accessory [Celestial Fragment].

The full deck is shown below. Please check the symbol at the upper right corner of each card for its category. Note that high-level cards are only obtainable when your corresponding skill level matches. Most cards are chosen to be either effortless or functional through [Discard] effects, enabling the player to accumulate synergies and retribution stacks almost infinitely.

To ensure an effective deck operation, the character must draw enough cards. [King of Swords] becomes highly potent after reducing its strain below zero with specific perks, especially since it's [Effortless]. Its 71% replication ability makes it remarkably efficient for replenishing your hand as well as decreasing your [Strain] with just one card. [Temperance] is chosen for its discard effect, allowing you to draw 4 cards without depleting your precious concentrations. [The Devil] and [N'Thael] are included to offset life costs from certain [Draw] effects.

[The Hermit] and [Knight of Pentacles] are selected for their discard effects, which permit drawing an additional card. Despite seemingly insignificant on their own, these effects can trigger defensive and retribution-related ripple effects gained from [Fortune Teller], significantly boosting base damage from [Wrath].

The late-game perks are listed below:

1. [Hightened Reflexes] further enhances retribution stacks induced by ripple effects.
2. Specific perks are selected to reduce [Strain], effectively reducing the AP cost of most cards to zero.
3. [Noctem Seer] and [Mental Defense] mitigate negative effects from [Vision] and [Knight of Pentacles].
4. [Noctem Oracle] grants the amulet [Noctem Oracle's Amulet]. It is very useful when no cards with [Draw] effects are available in hand.
5. [Notoriety] can eliminate enemies' immunity to [Sneak Attack] as long as you have [Resolve] (e.g., from [Lucid Dream]). However, it is not strictly required for this build because the [Sneak Attack] multiplier can still apply to AOE damage once your primary target is not immune to [Sneak Attack], even if other enemies affected by the AOE damage are immune to [Sneak Attack].
6. [Silver of Pain] is also very strong if you are not playing the game under the chosen difficulty. You can get [Silver] multiplier from [Multiplication] in the [Alchemy] card pool. [Alchemy] can be learned from the library in [Ravensburg Manor].

Gears for late game are shown below.
1.The accessory [Celestial Fragment] provides [Imbue] and [Draw 1] effortlessly, which is required to enable massive AOE damage.
2. The [Renegade's Leather Cloak] is used because it provides concealment, which is necessary to enable [Sneak Attack].
3. [Ring of Tenacity] is selected to compensate for the life cost from certain [Draw] Effects.
4. Other cards are chosen for their [Draw] effects.

The late-game skills are shown below. These skills are chosen to meet the requirements of specific cards. Leveling up attributes is not necessary, as they are not relevant to this build. Note that you can obtain the [Aeromancy] card pool from the library in [Ravensburg Manor]. [Aeromancer's Robe] can provide a [Draw] effect and [Chain] synergy, which has a chance to fully duplicate the damage of your first hit and apply that damage to a random enemy.

Please check the video below as a demonstration of the deck where the character deals 200,000+ AOE damage in the last battle:

Play Style:
1. Draw enough cards.
2. Use [Celestial Fragment] to get [Imbue], enabling high AOE damage.
3. Do not use cards that consume synergy before accumulating enough damage.
4. Trigger as many discard effects as possible to boost retribution, increasing damage from [Wrath]. You can use the discard effect [Envy] from [Queen of Pentacles] as an alternative reliable base damage source, where the damage depends on the HP you lost instead of retribution.
5. Accumulate 100% [Double] and [Quad], then accumulate as many [Sneak Attack] stacks as possible. (Most of the time, it is not necessary to get all the multipliers since the damage output is already substantial.)
6. Use [Eerie Melody] to deal massive AOE damage. Choose a target that is not immune to [Sneak Attack].
7. For any remaining enemies, repeat the cycle. You can use [Impeccable Strike] instead for quick single-target damage.
8. Apply stun during each cycle for defensive purposes (though it is not strictly necessary).

To further boost damage, [Multiplication] from Alchemy and [Critical Wound] from Marksman can be added to provide [Silver] and [Triple] damage multipliers, as shown below.

With all the damage multipliers added, the highest damage can exceed 100,000,000. The following video is attached as a demonstration. Now the character is Shadow Elf/Thespian for better retribution generation. These multipliers are not strictly required since the damage is already substantial.
Note that the [Silver] multiplier, similar to [Sneak Attack], can still apply to AOE damage once your primary target is weak to [Silver], even if other enemies affected by the AOE damage are immune to [Silver].

Thank you for reading this guide, and let me know your opinions on the build!