If a unit is moved to an open battlefield (with no opponent) using Cleave, does it gain the attacker designation and benefit from Assault for that turn?

Ruling: No. A unit only receives attacker or defender designations when combat occurs. Without an opponent on the battlefield, there is no combat, so the unit does not become an attacker and does not gain Assault benefits.

Nuances:

• The absence of an opponent means no combat designations are assigned
• Assault bonuses (such as +might against spells) only apply when a unit has the attacker designation from actual combat