Rule 904.1 · Archenemy
In the Archenemy variant, a team of players faces off against a single opponent strengthened with powerful scheme cards. The Archenemy variant uses all the normal rules for a Magic game, with the following additions.
Ask the judge Pro
The life counter has an AI judge that answers your play citing the exact rules. It is part of Gatewatch Pro; the rules, Oracle text and rulings stay free.