What is a good Energy curve?

Every deck in Riftbound: the League of Legends trading card game has an Energy curve, whether its player planned one or not. The curve is the spread of Energy costs across the 40 cards of the Main Deck, from the cheapest card to the most expensive. Drawn as a bar chart, it shows at a glance whether a deck can do something in its first turns and whether it has something worth a full board of runes later on.

How do you read an Energy curve?

An Energy curve counts every card of the Main Deck at the Energy cost printed in its top left corner, the chosen champion included. Legends, runes and battlefields have no cost and stay out of the count, and so does the Power cost under the number.

The table compares three ready-made decks. The Unleashed Champion Deck: Vex is low and wide, the Zed deck of the Vendetta Showdown Decks stops at 5 Energy, and the Lux deck of Proving Grounds leans on expensive spells.

The Vex and Zed decks are two of the six Champion Decks and Showdown Decks of Spiritforged, Unleashed and Vendetta, made for Fiora, Rumble, Vi, Vex, Zed and Shen. All six have an average cost between 2.9 and 3.3.

Why does the curve matter?

Your Energy grows by a fixed amount each turn. You channel two runes in each Channel Phase, so in a one-on-one Duel the player who goes first has 2 runes on their first turn, 4 on their second and 6 on their third, and the player who goes second has one more on each of those turns. Energy does not carry over, because the Rune Pool empties at the start of each Main Phase and at the end of each turn, under rule 167 of the Core Rules.

A good curve uses the runes as they come: a card that costs 2 on the first turn, a 4 or two 2s on the second, a 6 or two 3s on the third. The first turns count for a lot. Units enter play exhausted and exhaust to move, so a unit you play on your first turn can reach a battlefield on your second, and the player who gets there first is the first who can conquer and hold.

How many cheap cards does a deck need?

Most decks want about 15 to 20 cards that cost 2 Energy or less. Each of the six Champion Decks and Showdown Decks of Spiritforged, Unleashed and Vendetta holds between 15 and 20 such cards. Riot's Deckbuilding Primer, by game director Dave Guskin, asks for nine or more small units that cost 2 to 4, so that you reliably draw one by your first or second turn. It adds that this matters less when the Legend helps you fight for the battlefields early, as the Legend of Viktor, Herald of the Arcane, does.

The Vex deck plays three Wuju Apprentice and two Mutated Mouser, and the Zed deck plays three Punching Poro and three Shadow Order Disciple. All four units cost 2 Energy and no Power.

The numbers add up quickly. You shuffle 39 cards, since the chosen champion waits in the Champion Zone, and draw four. When 15 of those 39 cost 2 or less, the opening hand holds at least one of them about 87 times in 100. With 9, as in the Proving Grounds Lux Deck, it is about two hands in three. A mulligan helps, but it cannot find cheap cards a deck does not have.

Power symbols make a cheap card less cheap, since each Power you pay means recycling a rune, which takes it off the board. Punch First costs only 1 Energy but also two Body Power, so it needs two Body Runes and both leave the board.

How many expensive cards can a deck carry?

Only a few. The same six decks hold between none and five cards that cost 6 Energy or more, and no more than two that cost 7 or more. Without help from other cards, the first player has at most 6 runes on their third turn and 8 on their fourth, so an expensive card drawn early waits in your hand. An opening hand with two of them is often worth a mulligan.

A deck still needs some. From your fourth turn on you can have 8 runes or more, but your Draw Phase brings only one new card a turn, so a deck of nothing but cheap cards soon has more Energy than cards. Pick expensive cards that change the game when they land. Iascylla, the only card of the Vex deck that costs 7, is a unit with 6 Might that can pull an enemy unit to the battlefield it holds. A Legend can use spare Energy too: Herald of the Arcane plays a 1 Might Recruit unit token when you pay 1 Energy and exhaust it.

When should a curve be higher or lower?

The right curve depends on how the deck plans to win. The Zed Showdown Deck plays 12 units that cost 2 Energy and nothing above 5, so it can play a unit on its first turn and two or three cards in most turns after that.

The Proving Grounds Lux Deck goes the other way, with 15 cards that cost 6 or more, and the rest of the deck carries them. Its Legend, Lady of Luminosity, draws a card whenever you play a spell that costs 5 or more. Lux, Crownguard, the chosen champion the How to Play booklet recommends, can be exhausted to add 2 Energy for spells. The booklet tells the Lux player to take battlefields with the cheap units while waiting for spells such as Singularity at 6 Energy and Final Spark at 8.

Cards that add runes let any deck aim higher. Mobilize costs 2 Energy and channels a rune exhausted, which is 1 more Energy on every turn that follows. Cost reductions also let a deck play higher than its curve shows, since the curve counts the printed cost. Noxus Hopeful costs 4 Energy, and 2 less once you have played another card that turn. Sky Splitter costs 8 Energy, minus the highest Might among your units. Count such cards at the cost you expect to pay.

How do you check the curve of your own deck?

The deck builder draws the Energy curve while you build, with one bar for each cost from 0 to 7 or more and the average cost beside it. Its sample hand draws four cards from a fresh shuffle, so you can see how often the deck gives you an early play. Every deck among the shared decks shows its curve too, the ready-made decks included.

Once the curve looks right, the cards that fill each slot matter next. How many units, spells and gear a deck should run decides what the cheap and the expensive slots hold, and how many runes of each domain to bring decides whether the Power of those cards can be paid. A low curve like the Zed deck's suits an aggro deck that takes battlefields early, and a high curve like the Lux deck's suits the long game of a control deck, two of the deck archetypes players talk about.