Age of Empires 3: The Definitive Edition is set to get its latest DLC on May 2. Named Knights of the Mediterranean, this DLC will include two new civilisations, Italy and Malta. Two new game modes will also be introduced – Diplomacy and Tycoon (thanks Eurogamer).
According to the game's website, the Italians are a "Fabulously wealthy merchant republics, kingdoms, duchies, and even the Papacy had driven the Renaissance and dominated the trade networks of the Mediterranean. However, when the Italian polities were not engaged in conflicts abroad, they fought each other nearly incessantly, until the Risorgimento gave rise to the new Kingdom of Italy."
In terms of unique buildings, you can build a Basilica, which will boost nearby building speed and grant access to units like the Papal Guards, Schiavoni, Papal Lancers, and the Papal Zouaves. The Lombard will allow you to train Outlaws and Mercenaries and also grant access to a unique investment mechanic, which allows conversion of resources for free, but over time.
"One of the Mediterranean’s epitomes of a melting pot, Malta was strategically and financially important, and thus most of the surrounding powers coveted it, becoming a stronghold of the Knights Hospitaller."
Its unique buildings consist of the Hospital, which can heal idle units and even train Maltese infantry. The Commandery can train powerful European allies who are loyal to the Knights of St John. It also has a unique garrison system which allows units to be deployed from any other Commandery. The Depot boosts the attack power of all nearby gunpowder units, but will explode when destroyed, damaging surrounding units.
The Fixed Gun is exactly that, a massive cannon that's fixed in place for defensive purposes. And as for the hero of the civilisation, it's Grand Master Jean Parisot, the 49th Grand Master of the Order of Malta. He cannot die and can be rescued if he falls unconscious.
The Diplomacy and Tycoon game modes are new to the series and focus on building relations and enhancing the economy, rather than building armies and decimating your opponents. They seem like the perfect additions for those who like to turtle the game instead of going for all-out war.