Whenever one or more modified creatures you control attack, untap all modified creatures you control. After this phase, there is an additional combat phase. This ability triggers only once each turn. (Equipment, Auras you control, and counters are modifications.)
(18/02/2022)
An Aura controlled by an opponent does not cause a creature you control to be modified.
(18/02/2022)
A creature that is equipped is considered modified no matter who controls the Equipment that's attached to it.
(18/02/2022)
Notably, the triggered ability of Akki Battle Squad doesn't give you any additional main phases. This means that you will move directly from the end of combat step of one combat phase to the beginning of combat step of the next one.
(18/02/2022)
A creature with a counter on it is considered modified no matter what kind of counter it is or which player put it on that creature.
