Raids would last 6 days (one day break between event changes and to collect rewards), with each round lasting 48 hours, for a total of 3 rounds each raid event.
Initial matchmaking would group 10 players based on total hero might of their 72 strongest heroes, plus double the might value of a player’s strongest pet. Players would create 9 lineups (9 x 8 heroes = 72 total) to be used during raids from their available heroes. Lineups can be changed at any time, but changes would only reflect in the next 48 hour period.
Players would then have one battle against the other 9 players in their group, selecting one of their 9 lineups. A lineup can only be used once, and the AI would select which lineup you face of the other player. The AI will also only select each lineup once. Auto-battle is disabled for these battles.
Scoring is based on the win/loss record of each player, tiebreaker going to the player with the lower total might value. The top 3 players move up, the middle 4 stay in that tier, and the bottom 3 move down. As each raid event has 3 48 hour periods, this would result in 5 brackets total, and the rewards should scale accordingly both for which tier you are in, and your place in that tier each round. The lowest place in a higher tier should give more rewards than the highest spot in a lower tier.
If the game is unable to fill a match with 10 players, it can start with fewer, adjusting the number of attacks accordingly. Matchmaking after each round should attempt to still match players according to total raid might, but picking only from players in that tier.
Nice-to-have: The ability to watch other players in your group attack in real-time, and/or the ability to rewatch matches.