Haste
Battalion — Whenever this creature and at least two other creatures attack, creatures you control gain first strike and trample until end of turn and can't be blocked by creature tokens this turn.
The three attacking creatures don't have to be attacking the same player, planeswalker, or battle.
Once a battalion ability has triggered, it doesn't matter how many creatures are still attacking when that ability resolves.
The effects of battalion abilities vary from card to card. Read each card carefully.