Relentless Assault

Rulings

A creature that must attack each turn, must only attack once that turn. It is not forced into each attack that turn. — Abilities that trigger when a creature attacks, blocks, or is blocked will trigger during each combat that turn. Thus, a creature with Rampage will get the bonus added during each attack. — If you manage to cast this during a main phase of your opponent's turn, that opponent's creatures will untap and that opponent will be able to attack again. It will not allow you to attack during their turn. — It only creates an additional combat and main phase if it resolves during a main phase.