Salve, Civis Romanis!
It is the 2015th year since the founding of the City of Rome. Her empire is in the midst of accessing a new land, only discovered in the last century. These efforts come on the heels of a great calamity that has slowly but surely edged into the world of men – transforming the fauna and flora of the world into strange creatures while introducing strange new laws of nature that can be manipulated by the knowledgeable, pious, or naturally-endowed, to great effect.
You are a citizen of the Roman Empire. Rumors of great wealth and powerful artifacts in the Tainurian archipelagos across the Atlantic have reached your ears and for reasons of your own, you are on a ship to this new world. Many citizens such as yourself are traveling to these lands to find their fortunes. Go, citizen, see what fortune awaits you!
Start here if you’re playing in this campaign. That page can help with character creation both in using the mechanics of 5E and coming up with a background in the campaign world.