Assassin's Creed: Legends is one of the sequels to Assassin's Creed: Revelations. It takes place in the late 17th century and the early decades of the 18th century.
This is just a fan-made project. If you want to share your full opinion on the next Assassin's Creed game, feel free to comment. I'm just sharing my thoughts on what I believe should be the story for the next Assassin's Creed game.
200 Years Later...
200 years after the expusion of the Borgia family from the city of Rome, the Templars still continued to rule Italy from various power bases around Europe. By 1690, powerful Templar families began seizing control over major cities in Italy. The Templars of France, England, and Spain began to erode the Assassins' influence while storing their own, purging and destroying various Assassin guilds across Europe.
But the most crippling blow to the Brotherhood came in 1690. Rome, which served as the Assassins' headquarters in Italy and in Europe, was lost to the powerful Averidecci family, and the Grand Master of the Assassins (Piero's father) was killed. The Assassins of Rome and the Auditore family were wiped out while trying to hold Rome.
Piero, on the other hand, soughts to restore what his family fought for, and create his own legend.
The Story of Piero Auditore
As the last of the Auditore family, Piero's journey as an Assassin will take him across a completely hostile world. The only way Piero can restore Assassin influence and tip the scale against the Templars is to find a Piece of Eden. But when Ezio locked the Apple away in the Colosseum, the only Piece of Eden left in Italy is the Staff.
Piero will travel across Florence, Venice, Rome, Viana Castle, Masyaf, and Acre. The cities of the early modern age are more developed than in the Renaissance, and the technology is far more sophisticated.
After killing key Templars in the first 5 cities and restoring Assassin influence, Piero will have to infiltrate Acre, the headquarters of the Templar Order.. Though the Crusades are long over, the Templars continued to attack the Ottomans in a secretive war. Piero eventually finds Uberto Averidecci, the leader of the Templars and the one who ordered the Grand Purge that would destroy most of the Assassin Order.
Piero fights Uberto, but loses the Staff to him. Without the Piece of Eden, Piero is easily overpowered by the Templar leader and is mortally wounded. As the Templars are settling Acre, Uberto tells Piero that the Auditore family is finished, and kills him.
The Legend Afterwards...
After Piero's death, the Assassins continued to fight against the Templars, but they also began to lose. More lives join the Assassins' cause, but more are lost still. The Templars continued to have the advantage over the Assassins for the next 200 years, but the Assassin's Creed still remains appealing to most of humanity.