Due to the Black King's fragility under normal circumstances and how the card system works, White's pieces can become extremely dangerous foes with a combination of cards that boost them, and some of them are inherently dangerous even without buffs.
Queens
- As per Chess tradition, the Queen is the most dangerous piece on the board, capable of moving any unobstructed distance in any orthogonal or diagonal line, while also having a good amount of health in this game. While she moves at a slightly slower rate compared to most other pieces, this doesn't change how much she locks down the board with every movement. The Homecoming card Flavor Text even tells you that you're in for a rough ride after floor 3. If having to deal with one isn't enough, King's Mistress will reduce her maximum move distance to 3 (which is still nearly half a board) and spawns another Queen, Genderqueer adds a Queen on the board on turn 10 without giving any movement debuffs, and Succubus adds another one from the get-go while only giving you an extra soul slot. On the plus side, getting her soul after killing her is highly valuable as it lets you use her overpowered movement once.
- Queens with Iron Maiden — take the already-dangerous Queen and make her completely invulnerable, but make her move less often. Unlike King's Mistress, this doesn't affect the number of squares they can move, meaning that they can still move across the board to block important targets, threaten you, or cut off movement unless you have a Soul to spare. Any Pawn that promotes into a Queen will also become an invulnerable one, making the situation even worse. As an added slap in the face, their invincibility means you can no longer easily obtain the highly-useful Queen Souls from killing Queens. The only way to kill said Queens is via using King's Shoulders to throw them off the board, a very specific card that can only be used once per level. There's a reason why Iron Maiden is considered That One Disadvantage. While there is one way to remove their invulnerability, that requires the only pieces on the board to be Queens, which means picking Guillotine.
- Thankfully, this card did get nerfed into also removing one of Queens (and only appearing when you have 2+ Queens). While the invincible menace is still scary, at least you will not face four of them at once, and in fact are unlikely to face more than one. This also means it takes two cards to apply invulnerability, while also reducing Queen speed (making her more bearable) or giving you a soul slot (letting you escape her more easily).
- If you dare to reroll her Homecoming card, it will turn into the Tragic Homecoming card. She visibly gets angry on her card art, will be added to the board anyway, and all queens gain 2 HP. While it doesn't make her invincible like Iron Maiden, it still makes her terrifying with other Queen white card synergies such as Governess*. The Flavor Text even says to you "Better if you hadn't..."
Rooks
- The Castle white card lets Rooks instantly switch places with the white king if he would take damage, with the Rook taking damage instead. If you're on the same rank or file as the white king and the rook survives the attack, you'll be checkmated on the spot, and it's one of the reasons why Castle is considered That One Disadvantage. Fortunately, Castle got nerfed such that the Rook is stunned for one turn upon swapping, preventing it from checkmating you and making it merely annoying rather than deadly.
- Cathedral makes all non-Rook pieces near Rooks take 2 damage max per hit, forcing you to kill them if you want to deal any meaningful damage. It's even worse when paired with Divine Healing, allowing Bishops to undo half the damage you deal. It does unlock the very useful Church Organ card, but the drawback from Cathedral is often not worth it.
- Bunker is a stronger version of Cathedral, which makes all pieces near a rook take a single measly point of damage regardless of how many pellets hit a target. It synergizes even better with Divine Healing, and prevents your grenades from doing any major damage.
- Trowel makes Rooks get an extra 4 HP as long as a pawn is alive. Unless you can kill every Pawn in play, this makes Rooks into damage sponges for the level, and it's even worse if stacked with one of the above two.
- Mangonel turns Rooks into Long-Range Fighter Siege Engines. While they lose 1 speed, they gain the ability to target ANY tile with a boulder instead of moving. If White has multiple Rooks, they can keep forcing you to waste turns dodging their boulders, letting other pieces advance on your position quickly. If White has lots of Pawns up front, they can easily hinder you from getting into the backlines to deal with the constant boulder barrage.
- Tag Team lets Rooks swap positions with Bishops whenever either piece is about to move. This offers an alternative method for Bishops to apply pressure orthogonally like the White card Red Book. If you aren't paying attention, you may find yourself in check by a Rook that swapped with a Bishop or vise versa.
Bishops
- Bishops in general have arguably the most potential to become the biggest threat on the board, surpassing even queens.
- Bishops with Ascension and The Red Book. Ascension allows Bishops to move/attack past obstacles unhindered. The Red Book allows Bishops to move but not attack orthogonally, removing their greatest weakness of only moving on similar-colored squares. When combined, Bishops essentially get the movement of Queens that are unblocked by other units and unhindered by The Moat. Throw in Zealots, and you essentially have multiple Queens that attack over other pieces, every other turn. Worse still, you do not get their enhanced movement capabilities when using their souls.
- Divine Healing Turns Bishops into The Medic, letting them heal ALL white pieces in a 5x5 area centered around themselves by 1 hit point. 1 hit point doesn't seem like much, but this hard counters cards that rely on attrition or light damage, like Ravenous Rats and Wand of Downpour, and AoE, like Kingly Alms or A Piercing Truth. If the amount of bishops on the field is greater than 4, you better hope you can kill pieces in one hit. May the game have mercy on your soul if Cathedral is in play as well.
- Theocracy might remove the king, but it means you have to kill every single bishop to finish the floor, and they gain 2 hit points to add insult to injury. If there are too many bishops, the game turns into whack-a-bishop, as bishops with their superior mobility to the white king may decide to move into hard to reach locations, forcing you to chase them down. Pawns can also become problematic because there's always the possibility of a pawn promoting into yet another bishop.
Knights
- Knights with both Kite Shield and Bodyguard. Kite Shield gives all the otherwise-fragile but fast Knights a Single-Use Shield, meaning that they will take at least 2 turns to die. Bodyguard makes it such that the King cannot die if a Knight lives and it gives 1 HP to Knights. Put both together and you're forced to kill mobile enemies that can jump over other pieces and will take at least 2 turns to die.
- Knightmare makes Knights have 1 less health but they become intangible on any turn they aren't about to move while still being able to check you. It's not that bad on its own, but much more annoying when combined with Bodyguard or Kite Shield.
- Saddle allows Knights to carry adjacent non-Knight, non-Rook pieces with them whenever they move, should there be an empty space for the passengers. This means that with the proper position at the start, they can quickly get the Queen into play from behind the pawns, to say nothing about sending Pawns quickly down the lane for promotion.
- Unicorn Lets Knights charge in a straight line like a Rook which doesn't end your run directly, but instead inflicts knockback. This is one of the most dangerous counters to Cornered Despot* because Unicorn lets Knights end your run by Ring Out from accross the board.
Pawns
- By themselves, Militia* and Pikemen* are manageable. Both of them put together turns Pawns into a Zerg Rush of Instant-Death Radii that can block off huge sections of the map or chase you down and corner you, as the Pikemen 2-square range now extends to all four cardinal directions
◊ to threaten 12 squares in total instead of the usual 2, or 4 if Militia/Pikemen are separate. Adding Assault*, Pillage*, Zealots* and/or Scouting* to this will make Pawns into a fast-moving Advancing Wall of Doom that you will need to take out quickly or risk certain death. Fortunately, Pikemen got nerfed and Pawns with it can no longer attack diagonally, preventing "Instant Death" Radius Pawns from existing anymore. - Revolution and Pillage adds 6 and 5 pawns respectively. While pawns on their own aren't threatening initially, the sheer amount of them means there's a ton of extra bodies you need to blast through. Even if you survive the initial Zerg Rush, there's always the threat of mass promotion after a moderate amount of turns. Pillage in particular is deadly if combined with Full Plate Armor, buffing the small 3 HP of pawns into a beefy 5, letting them absorb a lot more shotgun shells for more dangerous pieces.
- Undead Armies spawns a pawn wherever a non pawn piece is killed, and reduces pawn HP by 1. Doesn't seem too problematic... until that [insert other piece] charges right down the board close to the bottom. When you kill that piece, suddenly there's a pawn within spitting distance of the bottom row, ready to promote... If you kill that promoted pawn piece it'll spawn another pawn... which is likely next to the bottom... and- you see where this is going. The only saving grace is that non-pawn pieces on the lowest rank of the map don't spawn pawns when they die.
- Conscription can at first seem mostly controllable, as a steady stream of Pawns on the back of the board once every five turns isn't that big a deal, but then you add Lookout Tower, which causes backup cards to advance an extra tick every time you kill anything. Anything. Including all those pawns. Anything more than just one Conscription and one Lookout together can quickly result in an unending tide of little white pieces trampling down the board faster than you can kill them.
