When a unit with Cleave moves to a battlefield, is the Assault bonus a passive effect or a trigger ability that the opponent can react to? Similarly, can an opponent react to Shield when a unit with Shield moves to their battlefield?

Ruling: Assault and Shield are passive abilities, not triggers. When a unit with Cleave moves to a battlefield, it instantly gains the Assault might bonus without creating a reaction window.

Sequence:

• If the unit has no move triggers: The unit moves to the battlefield and instantly gains the Assault bonus with no opportunity to respond
• If the unit has move triggers: The unit arrives at the battlefield, the move trigger goes on the chain (allowing responses), and the Assault bonus applies only after that chain fully resolves

Nuances:

• Units with move triggers are considered at the battlefield when their move trigger is on the chain, but combat has not yet begun
• If a unit with Cleave and a move trigger initiates combat, opponents can respond to the move trigger (e.g., with Gust) before the Assault bonus applies and combat begins
• If combat is already ongoing at the battlefield and the unit joins as the attacker, it gets the Assault bonus before the move trigger chain fully resolves
• There is no "move limbo" - permanents are either at their Origin before moving or their Destination after moving