This page summarises the different types of decks (a.k.a. SOUL Types and Classes) available as well as their general play style.
To see previous versions of these soul types go here.
For deck builds and further strategies go here.
There are seven different decks based on the SOUL attributes described in the game of Undertale. Each deck has its own unique ability as well as Effect Cards to go with it. Deck specific cards can be identified by the matching colour of their name at the top of the card.
In order to complete a deck one must have exactly 25 in it. This can be achieved by clicking on Cards, then Decks in the main menu and then clicking on the cards you wish to add to your deck (more info here). If you are new to the game, it is recommended to keep at least 3 Taunts in every deck as well as a Scarf Mouse or Nacarat Jester (who can Silence). Echo Flower is also a really good card for beginners.
This deck is suggested for newcomers and experienced players. It has a great comeback rate, focusing more on learning from trial and error and hanging on until an opportune moment arises. Its ability is having 1 extra life. When reaching zero hp, instead of dying, you lose one of these lives and gain 25 hp. A tactic used by people of this deck is to wait until their health is low and the opponent has their best cards out, then use 'Hyper Goner' to remove all enemy cards from the field, and resurrect their best cards using 'Resurrection' for a counter attack. Good cards to use with this deck are Asgore, Golden Flowers, Frisk, Chara and Asriel Dreemurr. The latter to bring your health back up if really low, and the former to be used after 'Woshua', since Asgore kills damaged enemy monsters and Woshua deals damage to them. Alternatively, Woshua can be used to deal 1 damage to all enemy cards on the field after having used Same Fate.
This deck is suggested for more senior players. The main ability of Patience is preventing monsters from attacking sometimes, and damaging any paralysed one. As such many of the cards for this deck are focused around surviving long enough to get better, stronger cards on the field. It is particularly effective against Kindness and Integrity as these decks are more about using strong monsters that you can paralyse instead of being based on spells. People playing this deck should probably have a lot of taunt or high health cards. A typical strategy involves waiting for the opponent to have a full board, use 'Cold Winter', and then 'Defrosting'. Players of this deck may also use monsters such as The Heroine or Mettaton NEO and apply taunt to them using 'Protection'. One may also wait until the opponent has a full board, make sure you have 2 cheap cards on your side and then use 'Snow Storm' to turn the board into weaker monsters, hoping to have luck. Mettaton and Mad Dummy are good cards to apply taunt to via 'Protection' as they typically last multiple turns; using then Fridge on them is even better. It is highly suggested to have lots of Cold Winter cards in this deck.
This deck is suggested for more senior players, however is decent for newcomers if they use mostly cheap cards. Bravery has the ability to draw 4 cards for the player at the start of their turn. It focuses more on the attack of its monsters, aiming to deal massive amounts of damage in few turns with the right setup, but it may be based on taunt spamming, or moving trough your deck fast and finding a specific and deadly combination of cards. People may choose to have a lot of Waterfall related cards, such as Aaron, Shyren for healing, and Woshua, as well as some taunt cards. A good number of cards around the 4-7 cost range protected by monsters with taunt is a good idea for this deck as monsters can have their attack increased substantially with Effect Cards in this deck. Having a deck centred around cheaper cards is also a good idea, especially with Burgerpants. This is known as a 'Bravery Zoo', where cards are spammed quickly and continuously to overwhelm the opponent before they can place substantial cards. If using this method, 'Assault' is a good card to use, so you won't ran out of cards, as although risky it can often give you cards such as flowey, and even cards gained by Assault such as Snowman can be valuable with 'Strength'. This quick drawing can be a disadvantage against decks such as determination, perseverance or taunt spammers, since these decks can get rid of your cards easily, although if facing Bravery it's important to keep your guard up as it can remove the taunt from a card using 'Penetration'. If going for an aggressive approach it is advised to choose cheaper cards such as Temmie, Monster Kid, Ice Cap and Snowdrake.
This deck is suggested for all players. Integrity now returns 20% of a card's cost when played (rounded down). This soul type is great for dealing out quick bouts of damage before the enemy can get a card out. Temmies and other cheap monsters with charge are decent in this deck. A combination of cheap cards with taunts and a few higher end cards is a decent option. Other cards which can give you extra monsters such as So Sorry and Alphys are also good choices. Using a Temmie, then bringing it back with with 'Break' is useful as it means you can use it to attack more than once in a turn if you have the money as well as acquire additional Temmies. Using Break or Doggo in this deck and using them on Burgerpants in a similar manner is also a good choice. People using this deck may probably seek to use more costly cards mixed with taunts. A use of Integrity that was popular a while ago (not confirmed), but still works (confirmed) is to make a dog deck, essentially creating a deck comprised almost solely of dogs. The varied abilities of each dog, as well as their prices compliment each other well. Having multiple Dogamys and Dogaressas in the deck and putting them back into your hand to place them back onto the board again with cards like 'Break' or Doggo creates a good synergy by making use of their stat boost Magic. Integrity is also used as a 'control deck' by more senior players. Cards which freeze or remove opponent cards from the board such as 'Expulsion', 'Snowdrake's Mom', or 'Endogeny' are used to control the opponent's board essentially preventing them from making any meaningful plays. Typically weak against Bravery if using Burgerpants.
This deck is suggested for intermediate players and above. It is about poisoning damaged enemy monsters with karmic retribution (KR). Cards under KR lose 1HP at the start of their turn (can die from it ). The ways to remove KR without killing the card are to silence it, use asriel or call it back to the deck/hand. A common practice for this deck is to use 'Pollutant Gas' when the enemy board is full or use 'Poison'/'Woshua' and then use 'Worsening', 'Termination' or 'Contamination' on poisoned monsters. Any type of card can be used in this deck however cards such as Flowey, Asgore, Woshua, Golden Flowers or Heats Flamesman are good choices. Perseverance is a hard deck to create combos for, however it's mostly played with the intent of clearing the board or killing selecting monsters so a mild rush/zoo or control deck are viable options. Perseverance relies heavily on card drawing and multiple Spells, therefore cards that can draw or summon other cards like So Sorry, Gyftrot, Igloo, and Chilldrake are also useful additions. Effective against decks based on few powerfull monsters.
This deck is suggested for beginners. The soul type heals the player for 2hp every time you end your turn as well as all ally monsters for 1hp each of your turns. This makes it good against the Justice deck as it heals more than the damage the Justice deck can dish out each turn via its ability, however Justice deals its damage before Kindness heals, so if a monster is at 1HP and gets targeted by Justice's ability it will die. Kindness focuses more on healing, a good tactic for kindness is to use 'Longevity' on a monster with taunt or to use one of the other healing cards for the same purpose. Typically those using this deck may want to opt for a longer 'wait it out' style of battle, this is done by having many taunts and medium to higher costing cards until you have enough gold to deploy them. A possible, but risky tactic is to create a OTK (one turn kill) deck by using many 'Force of Natures' before using 'Longevity' on a high HP card before switching the health and attack around with Madjick; or by using Feast and going for an OTK with Papyrus statue, Heal, Shyren and the already present monsters. Players of this deck are decently dependent on using Effect Cards for particular playstyles, often cards will either be too expensive to place or you will not have enough cards, so Burgerpants or cards like Chilldrake or Igloo are useful. This along with Determination can be a good all rounder deck for newcomers. Other useful cards include Snowdrake, Asriel, Monster Kid, Janitor, Grillby, and Pyrope.
This deck is suggested for higher end intermediate players and above. At the end of the turn of a Justice user, they will deal 1 damage to a random enemy card + 1 to the player if they have more hp. This ability will take place before Kindness heals, so a Kindness opponent owning a card with 1HP will be destroyed at the end of the turn if hit. All Effect Cards of this class deal some form of damage, because of this it is important to note that Effect Cards for Justice are often more expensive than those for other soul types. Dealing damage in the way these cards do is essentially the equivalent of having a charge card which ignores taunt. Because of this, it is more expensive than other damage dealing cards from other classes/soul types which have situational damage. These cards used to be cheaper until they were nerfed, but have since been re-adjusted multiple times, despite this they are still extremely effective and allow for some of the best combinations in game. Keeping a handful of 'Punishment' and 'Undyne's Spears' handy gives the player a great advantage when wanting to quickly dispatch an enemy monster or deal the finishing blow by bypassing taunt. Undyne is often used in this deck, it is especially good with Asgore, Woshua, and Heats Flamesman. Other cards which deal damage such as Vulkin, Moldessa, and Tsunderplane are highly useful. Justice typically uses a heavy board control playstyle with various select damage and split damage cards and can excel at most stages of a game if played correctly. Decently Effective against Bravery Zoo, and Determination, typically slightly weaker against Kindness.