Piltover and Bandle City have formed an alliance, with the following effects:
- Diplomatic pact. Their diplomatic options vis-a-vis Demacia and Zaun will be restricted. For example, neither side will be able to ally up with Zaun unless both sides agree. Also, each faction will be obligated to assist the other to react to a disaster or defend against an invasion.
- Featured Match bonus points. If either faction wins bonus points from Featured Matches, those points will be shared equally between both Piltover and Bandle City.
- Summoner substitution. Unlimited Summoner substitution is allowed for Piltover and Bandle City in all matches, including Featured Matches and Tournaments, so long as they are not fighting one another.
- Champion substitution. Piltover may borrow one Champion from Bandle City in each match, and vice versa. (Champions who are already shared, such as Heimerdinger, do not count against this limit.) However, Rumble will never fight for Piltover.
- Research surge. The first week after ratification, each faction will receive a +2 cooperation bonus on all research rolls for that week.
- Combined research. Each week, each faction will receive help from its ally on one project, chosen by staff, generally after informal consultation with members of that faction. On that project, the ally will contribute a second research roll. This bonus would not apply during the “surge” week immediately after ratification.
- Joint victory. If either faction wins the arc, Summoners from both factions will participate in the vote to select a faction for the next storyline. They will also share the pyrikhos, with the “actual winner” getting two-thirds and their ally getting one-third.