Arkhosia - The Draconic Isles
Here is a quick guide to give you an idea of where your characters fit in regards to the relative power levels of the campaign.
At Level 12 your PC’s are definitely nearing the top tier of individual power in the known world.
The Dragonguard for example who are the main “police” of each island and the rank and file of each overlords dragonborn army are approximately Level 5. Very powerful compared to the normal citizen but no match individually for might warriors, warlocks and magic users such as yourselves.
The captains within the Draganguard will be within the L6 region with their commanders at L7.
The elite guard of the dragon overlords may be closer to L10 with perhaps individual champions at your level or beyond.
The dragon overlords themselves vary quite wildly in power but would start at about L14 for the smallest islands ranging to about L20 and beyond for the most powerful known dragons.
Tyraxus for example – the dragon overlord for the island in which the campaign begins is one of the most powerful dragons in Arkhosia and is L20.
The Sea Kings also vary quite a lot in power – individually they would range from about L5-L15+.