Setup:

Protagonist: Prince with Almighty Boost and Synthesis Boost. Here to use the Royal Sword synthesis skill as our main form of damage.

Almighty damage DOES suck but we can stack boosts here to make it pretty decent.

Oh and also has Medica to top the party up as necessary.

Strohl: Royal Warrior with Shelter Formation. Here to buff our defense, but mostly to pass on a turn so we can use Synthesis every turn.

Hulkenburg: Royal Knight. Here to stay on the back line and use Holy Knight’s Proclamation to tank for the party. Any single-target attacks went onto her, where they did minimal damage.

Junah: Masked Dancer with the Trickster mask on. Here to sharply debuff the dragon’s attack and defence every turn. This had two benefits: 1) It means the dragon wastes a turn rebuffing itself each time 2) Means we can do a lot more damage to it

The only time we were in any danger at all was when the dragon used its breath weapons multiple times in a turn and everyone got status ailments.

Which, I have a gripe about

There are too many fucking status ailments in this game. I have no idea what half of them do.