Two teams of two share one life total of 30, take their turns together and lose as a team at 0 life or 15 poison.
The rule
Two-Headed Giant is played by two teams of two. Each team sits together on one side of the table, facing the other team (CR 810.3).
A team shares its life total, starting at 30 (CR 810.4, CR 103.4a). Damage and life loss to either player come off the team's total. Poison counters are shared too, and a team with 15 or more loses (CR 810.10, CR 704.6b, CR 810.8d). Everything else, such as energy or the cards in hand, stays with each player (CR 810.5).
Teammates take their turns together (CR 810.2, CR 810.7, CR 805), so there is a starting team instead of a starting player (CR 103.1a). Larger teams get 15 more life and 5 more poison per player beyond the second (CR 810.11).
In Life Counter
Pick Two-Headed Giant at setup and the app seats each team on its own side with one shared area: one life total of 30, one poison count with the limit of 15, and each head's own counters on the team area. The roll for the first turn picks a team.
