First fight: Captain Trotter
Watch his stance so your attack type is not rejected. His Drink warning gives you an action before Inferno; keep Ghost Potion or another valid protection response available for that charged window.
Final fight: The Ancients
Clear the summoned Vessels before targeting the boss. Prepare protection before Ultra Beam and keep tracking the move loop when Darkness hides HP and status information.
After Firebrand
Return for the story handoff toward Chapter 5. Finn McCool is now an optional detour at The Dunes Spot, south of Vermillion Village. The Ancients’ rematch uses Guru’s Guilty response.