Useful for catching your opponent off guard by summoning when you attack or attacked. Bronto can increase its attack significantly when gemini summoned, similar to Goggle Golem, and can then be switched back to attack during your turn. The A. Forces is for warrior type deck to increase each of your monsters' attacks. It's important to remember to not chain Arrivalrivals to your opponent's Wall of Disruption since your card will resolve first.
When you enter battle phase, activate Arrivalrivals from your hand first, then chain it with your Anti-Magic Arrows to be able to summon your monster and your opponent will not be able to chain their cards to it.