Relentless Assault

• WWizards of the Coast2025-09-19
  Official Ruling
  Relentless Assault creates an additional combat and main phase only if it resolves during a main phase.
• WWizards of the Coast2025-09-19
  Official Ruling
  A creature that attacks each turn if able must attack only once that turn. It is not forced into each attack that turn. However, a creature that attacks each combat if able must attack again if it can.
• WWizards of the Coast2025-09-19
  Official Ruling
  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.
• WWizards of the Coast2025-09-19
  Official Ruling
  Abilities that trigger when a creature attacks, blocks, or is blocked will trigger during each combat that turn.

Rulings via Scryfall