How does 2v2 (Magma Chamber) work?

Magma Chamber is the team mode of Riftbound: the League of Legends trading card game. Four players sit down in two teams of two, and each player brings a deck of their own, with its own Legend, runes and battlefields. The two players of a team share one score, play to 11 points instead of 8, and win or lose together. The Core Rules on Riot's Rules Hub list the mode as 2v2 (Magma Chamber) in rule 491, one of the five sanctioned modes of play.

Every player takes their own turns and fights with their own units, as in a Duel. A handful of team rules decide what teammates share, what they keep apart and how a shared score is counted.

How is a game of Magma Chamber set up?

Each player brings a full deck with three battlefields, as in every mode. Two teammates may not play the same Champion Legend, and they may not bring the same battlefields, so a team settles its two decks together.

The turn order is settled first, because it decides the battlefields. The player who goes first puts none of their battlefields in play. The other three players each pick one of their three at random, so three battlefields stand in the middle of the table: one from the first player's teammate and two from the other team.

Turns alternate between the teams: the first player, then an opponent, then the first player's teammate, then the other opponent. When teammates sit across from each other, turns go clockwise as usual. When they sit side by side, as the Tournament Rules seat them at events, turns pass across the table. The first turn is evened out as in War: the player who goes first does not draw a card in their first Draw Phase, and the player who goes last channels an extra rune in their first Channel Phase.

What do teammates share, and what do they keep apart?

Teammates share their score. Both players of a team always have the same number of points: when either of them gains or loses a point, the team does, and a card that checks whether a player gains points checks that player's team. When one player concedes or loses, the whole team loses.

The word friendly also reaches across the table. Your teammate's units and gear count as friendly to you, so a card that chooses a friendly unit may choose one of theirs. Blind Monk buffs a friendly unit and Eye of Twilight gives one Tank, and either can pick a unit of your teammate. Some Legends name the ally outright. Gloomist lets you exhaust it to draw a card, and Chem-Baroness to get a Gold gear token, when you or an ally hold a battlefield.

Everything else stays apart. Each player keeps their own hand, runes, Energy, Power and XP, and control is not shared. You cannot make a standard move with your teammate's units, you cannot hide a card at a battlefield your teammate controls, and your units cannot move to a battlefield where your teammate has units. Your hand stays private, but you may show it to your teammate at any time. At events, the Tournament Rules allow and encourage talk between teammates, as long as it does not slow the game down.

Can you play cards on your teammate's turn?

Yes, in two ways. In your teammate's Main Phase, you may play spells and use abilities when your teammate uses their own Priority to invite you, and that includes spells and abilities without Action or Reaction. The ability of Blind Monk has neither keyword, so you use it in your own Main Phase, or in your teammate's when they invite you.

In a showdown, nobody needs an invitation. Focus goes around the whole table in turn order, so all four players can play cards with Action or Reaction. A fight itself still involves only two players, because combat happens between the units of exactly two players. Since teammates never share a battlefield, every combat is fought between one player from each team. A Reaction such as Against the Odds, Tactical Retreat or Not So Fast can save a unit of your teammate in the middle of their fight.

How does a team score its points?

A team scores battlefields in the same two ways as a single player, by conquering and holding, with two limits. Each battlefield can be scored only once per team per turn. And a battlefield your teammate controls at the scoring step of your Beginning Phase cannot be scored by your team on your turn at all, neither by holding nor by conquering.

In practice, each battlefield your team keeps scores once per round of turns, on the turn of the teammate who controls it. Say you control one battlefield and your teammate another when your turn begins. You hold yours for 1 point, and theirs scores when your teammate holds it at the start of their own turn. The rule also closes a loophole: you cannot have your teammate's units leave a battlefield and then score it by conquering it yourself.

From 16 October 2026, the final point rule is adjusted for the team. The Core Rules of 9 October 2026 take effect on that day with the Radiance update, and Riot's patch notes say the earlier 2v2 scoring rules were slightly contradictory and are now fully aligned. Before that day, the Vendetta rules update, in force from 24 July 2026, counted a battlefield held by your teammate toward the final point rule.

With 10 points, a team gets its eleventh point from a conquer only if the player who conquers has scored every battlefield that turn, leaving out any that their teammate controlled at the scoring step. Points from holding are not limited. Say your team has 9 points and your teammate controls one of the three battlefields. You hold a second one at the start of your turn for the tenth point, then conquer the third, and that conquer gives the eleventh point and the win.

Running out of cards costs the whole team. A player who burns out chooses an opponent to gain 1 point, and since both opponents share a score, the point always goes to the other team.

Which Legends and decks suit Magma Chamber?

A Legend whose ability reaches friendly units reaches your teammate's units as well, which can make it far stronger in a team. Riot keeps a separate banned list for 2v2 Constructed because of one such Legend. The list holds every card and battlefield banned in Constructed, plus Wuju Bladesman of Master Yi, banned in 2v2 since 24 July 2026, which gives +2 Might to a friendly unit that defends alone. In its July ban list update, Riot explained that because the bonus covers both teammates, it gave a team far more strength from the start of the game than was healthy. The banned lists apply at sanctioned events, and at home the players decide.

As advice for a first game, pick two decks that do different jobs. Your units cannot join your teammate's battlefield, so each of you usually looks after a battlefield of your own, and a deck that holds a battlefield well pairs nicely with one that attacks. Keep a Reaction or two for your teammate's fights. An opponent always plays between your turn and your teammate's, so a battlefield you leave weak can fall before your teammate gets to help.

The Proving Grounds starter box holds four ready-made decks with four different Legends and four different battlefields, so one box is enough to try Magma Chamber at home. At stores, Magma Chamber is played at some Nexus Nights and at 2v2 events, where the two players of a team sign up and sit down together. Magma Chamber needs exactly four players, so a group of three plays Skirmish instead. The Legends and battlefields pages help a team pick its two decks.