Learn · Deckbuilding
Build it legal, then build it functional
A Riftbound deck has a very small legal skeleton and a very large amount of room inside it. This page keeps those two things apart: first what a judge checks, then the decisions that decide whether the thing works, and finally one deck assembled end to end so you can see the order the choices come in.
Numbers last checked 28 Aug 2026· From the Core Rules and Tournament Rules of 16 Jul 2026
First half
The checklist a judge reads
These nine lines are the whole of what makes a deck legal. Satisfy them and your list can be registered. Everything after them on this page is about whether it wins, which is a different question.
| Requirement | Count | Detail |
|---|---|---|
| Champion Legend | 1 | One, in the Legend Zone. It never enters play, cannot be killed and cannot be moved, so its ability is simply always on. |
| Chosen Champion | 1 | One, face up in the Champion Zone from the start. It must be a champion unit whose champion tag matches your Legend. A Signature card can never take this slot, even with the right tag. |
| Main deck | 40 | The Core Rules set a floor of 40. Sanctioned constructed competition requires exactly 40 under the Tournament Rules, so build 40 and stop thinking about it. Your Chosen Champion occupies one of those slots. |
| Copies per name | 3 | Three at most per card name, counting the Chosen Champion, and counted across main deck and sideboard together. The same character under a different card name is a separate three of. |
| Signature cards | 3 | Three in total across the whole deck, not three of each. All three must carry your Legend's champion tag, and none of them may sit in the Champion Zone. |
| Rune deck | 12 | Exactly twelve, shuffled and kept separate from the main deck. All of them inside your Domain Identity, with no per colour limit at all: twelve of one rune is a legal rune deck. |
| Battlefields | 3 | Three registered for a two player game, no two sharing a name. A Battlefield that carries a domain sits under your Domain Identity like everything else. |
| Sideboard | 10 | Ten cards or fewer, and only at events whose format allows one. Every card in it must be legal in your main deck already. |
| Domain Identity | · | Every card in the deck, runes included, sits inside your Legend's domains. Read the next section carefully, because this is the rule most often stated wrongly. |
Notice what is not on that list. There is no minimum unit count, no maximum, no cap on spells, and no rule saying your curve has to look like anything at all. Everything in the second half of this page is a decision, not a requirement.
The rule most often stated wrongly
Domain Identity is a containment rule, not a two colour rule
Your Champion Legend's domains are your deck's Domain Identity, and every card you register has to fit inside it. The rule as written is about containment. It says nothing about how many colours there are.
- A card with one domain is legal if that domain is in your identity.
- A card with several domains is legal only if your identity contains all of them, not merely one of them.
- The rune deck follows the same rule. An off domain rune is illegal even though it is a basic rune.
- Some game effects let you add cards to your deck irrespective of domain. Those cards then count as part of the deck's Domain Identity themselves.
Why we do not write "a Legend has two colours"
Plenty of guides say a Legend fixes your deck at exactly two colours. In practice most printed Legends do carry two domains, but no rule pins the number at two. What the rule says is that cards must be contained by the identity the Legend defines, so that is what we write. On the day Riot prints a Legend that is not two domains, the sentence written from the rule will still be correct.
The six domains Before you pick a Legend, know what each colour actually wants to do. That page covers all six without ranking any of them.
The deck's spine
The Chosen Champion, and Signature cards
One champion unit starts the game face up in your Champion Zone, and you may play it straight out of there the moment you can pay for it. It is the one card you know you will draw in every single game.
- It must share a champion tag with your Legend. The tag is what matters, not the character's name.
- A Signature card is never a champion unit and can never take this slot, even when it carries the right tag.
- It still counts against the three copy limit. One in the zone plus two more in the main deck is legal, and is often correct.
- During play, any copy of that named card anywhere counts as your Chosen Champion for rules and effects that care.
Signature cards: three, total
- Signature is a supertype rather than a card type, so a Signature card can be a spell, a unit or a piece of gear.
- Three is the total for the deck, not three of each. Three copies of one Signature spell spends the whole allowance.
- All of them must carry your Legend's champion tag. Somebody else's Signature card is illegal even when its domains fit.
- A card marked Unique is limited to one copy, and still occupies a Signature slot if it is Signature.
Second half
Curve in Riftbound is not the number you think it is
The question worth asking is not what your average card costs. It is what you can play on turn three and still have something left to act with. Four facts explain why.
- You channel two runes a turn
- Turn one you have two runes. Turn two, four. Turn three, six. The player going second channels one extra rune during their own first Channel Phase, which is the game's compensation for the single turn of disadvantage.
- A rune spent on Power leaves play
- It is recycled to the bottom of a twelve card deck. Pay three Power across your first three turns and you are on three runes, not six. Players who never count this feel permanently rune starved without knowing why.
- The Rune Pool empties at the start of the Main Phase
- Unspent Energy and Power are lost rather than carried, and the pool empties a second time during the Ending Phase. Saving up for a big turn is therefore not a plan.
- Units arrive exhausted
- A unit you play on turn three cannot move until turn four unless you pay its Accelerate cost. A card that looks on time on paper is usually a turn later than that.
Test the deck on turn three
Deal yourself an opening four, mulligan as you actually would, and play out three turns against nobody. If a third of your hands cannot make a board play by turn three, the deck is too expensive regardless of how good the expensive cards are.
The twelve nobody thinks about
Split the runes by counting symbols, not cards
The rune deck has no per colour limit at all. Twelve of one is legal; so is six and six, and so is nine and three. The right split is not a rule of thumb, it is arithmetic you can finish in ten minutes.
- 1
Go through all forty main deck cards and count Power symbols rather than cards. A card with two symbols of the same colour counts as two; a card with no symbols counts as nothing.
- 2
Split the twelve runes roughly in the ratio of those counts.
- 3
Then look at when each domain's symbols appear. A domain you need on turn two needs more runes than one you need on turn five, even if the totals match, because a turn two rune has to already be in play.
- Spending Power is a real cost. A deck full of two symbol cards is not only harder to cast, it eats its own resource base, which quietly makes cards with no Power cost better than they look.
- Power that can be spent on any domain softens an awkward split without changing the rune deck at all. If your deck has a source of it, your split has more room than the count suggests.
The three slots people fill without thinking
Three Battlefields, one of which you actually play
You register three Battlefields, and exactly one of yours is used per game, alongside exactly one of your opponent's. How you get to choose depends on the format.
- Best of one
- Each player selects one of their three at random and the other two are removed. Bring three you are happy to play, because you do not get to pick.
- Best of three
- Each player chooses one. Over a match you will play at least two of the three you brought.
- No duplicate names
- You cannot register the same Battlefield twice, so these three slots are always three genuinely different cards.
The best of three detail most guides skip
After a game somebody won, the two Battlefields that were in play are removed from the rest of the match, and both players pick again from what they set aside. That means your second and third Battlefields are not spares: they are the plan for game two and game three, which are the games your opponent already knows what you are doing.
Only where an event has one
The ten card sideboard
A sideboard is not part of a deck. It exists only in competitions whose format allows one, and the rules around it are tighter than most players assume.
- Ten cards or fewer, and only cards that would be legal in your main deck.
- The three copy limit spans main deck and sideboard together, so four copies split across the two is still illegal.
- Cards are swapped one for one, and your main deck must still meet its size requirement afterwards.
- You may change your Chosen Champion to one from your sideboard or main deck, as long as its tag matches your Legend. This is the lever people forget they have.
- You may not change your runes, your Legend or your Battlefields at any point after registration.
- No sideboarding before game one of a match.
Do it
One deck, assembled end to end
These five steps are the order we actually use. The example is built around Loose Cannon, a Legend that draws you a card when your hand runs low. That is a plan you can state in one sentence, and a plan you can state in one sentence is a plan you can check every card against.
Pick the Legend you want to play, not the one that looks strongest
A Legend's ability fires every turn of every game and you will read it a few hundred times. Loose Cannon draws you a card at the start of your Beginning Phase if you have one or fewer cards in hand, which turns the deck's plan into a single sentence: empty your hand every turn and get paid for it.
Pick the Chosen Champion from the units that share the tag
More than one champion unit carries the matching tag under this Legend, and they are different games. The cheaper one is a turn two or turn three play. The more expensive one rewards a discard plan. Decide which turn you intend to play it on before you move to the next step.
Fill the forty with threes first
Thirteen different cards at three copies each is thirty nine, plus your Chosen Champion, which is forty exactly. That is the most consistent shape a Riftbound deck can have. Start there and trade consistency for flexibility one card at a time, when a real game has shown you why.
Count the Power symbols and split the twelve
Follow the three steps above. For this example you have only two kinds of rune to choose between, because your Legend's Domain Identity already decided that. The ratio the count gives you is the answer, not the one that feels right.
Choose three Battlefields, and read what each gives your opponent
A Battlefield's passive applies to everything standing there, including your opponent's units, so one that adds Might to every unit helps the attacker as much as the defender. Choose for the pace you just built rather than for the biggest number on the card.
Do all five steps in the browser. The builder counts your sections, checks your Domain Identity and warns you the moment a name goes over three copies.
The last step is pricing. A deck's cost is not spread evenly across its cards: it concentrates in the Legend, the Chosen Champion and the Signature cards, while the remaining thirty odd main deck slots and all twelve runes are usually commons and uncommons. Build the cheap two thirds first and buy the expensive slots last.
Sealed uses a different set of numbers
Everything on this page is about Constructed. In Limited or Sealed you are given six booster packs and build a 25 card main deck, choosing any three domains or one domain plus the domains of a Champion Legend you opened, and every card you did not play is automatically your sideboard. If you are heading to a Pre-Rift event, that is the set of numbers to memorise.
Before you hand in the list
The mistakes that lose a deck check
Registering an illegal decklist is a game loss, not a warning, and the things people actually get caught on are the same lines this page just went through.
- The wrong number of cards in the main deck.
- Cards that are not legal in the format the event is using.
- More than three copies of a name, counted across main deck and sideboard.
- Cards whose domains fall outside the registered Legend's identity.
- A Chosen Champion whose tag does not match the Legend.
- Battlefields sharing a name, or fewer than three registered.
Next
Where to go from here
- The deck builderBuild a real list in the browser, with the legality checks this page just explained.
- The six domainsChoose the colour pair first, then choose the Legend.
- Tier listWhich Legends people are actually playing right now, with the reasoning.
- RulesKeep it open while you play, for the arguments this deck is about to start.
Every construction number on this page comes from Riot Games' Core Rules and Tournament Rules as updated on 16 July 2026, last checked 28 August 2026. ThaiRift is a fan site and is not endorsed by Riot Games. At an event, the judge is always the final word.