Ever since its introduction in 2007 – yes, the series is six years old – Ubisoft has established the Assassin's Creed franchise into one that truly defines this generation. The game not only focuses on nearly unstoppable assassin characters in the past, but also has tie-ins with a present-day storyline, and a small resistance group's battle with the evil Templars, running under the company Abstergo. As much as this story has been about Altair, Ezio and Connor, it's also been about Desmond.

With Assassin's Creed IV: Black Flag slated to arrive in just a few days' time – and present a "clean slate" on the story with the introduction of assassin/pirate Edward Kenway – we thought we'd take a brief look back at what the storyline of the series had to offer thus far. Warning, there are spoilers ahead, so if you haven't finished the games just yet, you might want to do that first.

Assassin's Creed (2007)

We're introduced to Desmond following his capture by Abstergo. They force him into a machine called the Animus, which co-aligns his memories of an assassin during the Third Crusade named Altair.

In the past, Altair's goal is to stop Robert de Sable from taking a Piece of Eden, while at the same time hunting down the Knights Templars to gain his place in the Brotherhood.

Altair does kill de Sable, but upon doing so, learns that one Templar still exists – Al Mualim, who possesses the Piece of Eden. He eventually finds and kills him, and recovers the Piece, discovering other artifacts around the world.

Meanwhile, back in the current day, Desmond is pulled from the Animus by Lucy Stillman, who's working with a small resistance as a mole within Abstergo. She explains that Desmond ties in with a bigger plot, as his memories could uncover a plot that could mean the end of the world in 2012.

Assassin's Creed II (2009)

After breaking out of Abstergo – where Desmond manages to hold off guards with newfound fighting skills – he and Lucky meet up with other members of the resistance, including a tech girl named Rebecca and a historian by the name of Shaun. They introduce another version of the Animus, where they connect him with another figure from the past – Ezio Auditore de Firenze, located in Florence, Italy.

The memories catch Ezio right when he witnesses the execution of his father and brothers at the hand of a corrupt official. The rest of his family goes into hiding while he learns the style of the assassin, vowing to get revenge. With the help of his uncle Mario and a resourceful Leonardo da Vinci, he begins wiping out Templars. He also learns about the Piece of Eden, introduced in the first game, which is in the hands of Borgia, in the form of an apple.

Ten years later, following years of service in the Brotherhood, Ezio learns that Borgia has become a Pope, and carries with him a staff that's also a Piece of Eden. He confronts Borgia, but lets him live, and uses both the apple and the staff to find a secret chamber, where he meets a virtual figure called Minerva. She allows Ezio to communicate with Desmond directly. She addresses the apocalyptic events that are to come – as they have repeated before in the past – and how Desmond is their only hope. Shortly after, Abstergo finds the resistance's hideout, forcing Desmond and the others to flee.

Assassin's Creed: Brotherhood (2010)

After escaping Abstergo, Desmond re-enters the Animus to learn more about the apple and the apocalyptic plot revealed at the end of AC II. There, Ezio returns to his home, only to find it under invasion by Cesare Borgia, the son of the Pope. His uncle Mario is killed as a result, and the apple is stolen. Ezio vows revenge and begins training young protégés in the art of the assassin.

Ezio comes face-to-face with Cesare, only to watch him poison his father with an apple of his own. Shortly after, he captures the corrupt son and retrieves the Piece of Eden once more. Cesare goes to prison soon after in Spain, but manages to escape with some help from his friends.

This leads to a big confrontation, where Ezio and his newfound Brotherhood face off against Cesare and the remains of his army. Ezio eventually wins, throwing Cesare to his death. He then takes the apple into hiding, leading Desmond to discover exactly where it is.

After finding the apple in the present day, Desmond is introduced to Juno, another holographic figure. She takes control of him and stabs Lucy after learning she had defected back to the Templars, and forces him to fall into a coma shortly thereafter.

Assassin's Creed: Revelations (2011)

This is one of the more significant entries in the series, as it introduces an older Ezio alongside Altair from the original game.

Still in a coma, Desmond awakens in a virtual world within the Animus, where he's introduced to Subject 16, an unfinished experiment. He explains that, following the death of Lucy, it's up to him to finish both Altair and Ezio's memories in order to regain consciousness. He eventually sacrifices himself so Desmond can continue his journey – not an easy decision, but one that has to be made.

Ezio's story begins years after Brotherhood, where he seeks out the origins of the Assassin in Masyaf. He finds Altair's library, a location that requires five keys to unlock, and learns that the Templars also want to get in and learn the Brotherhood's secrets.

Complications arise not only with a pair of brothers working for the Templars, but also with a love interest, Sofia Sartor. Eventually, Ezio kills one of the brothers, but finds himself banished from the city as a result.

Ezio eventually finds the keys and opens the library, where he catches up with Altair following the death of Al Mualim. He lost a wife and child on his way into the Brotherhood, but eventually got revenge and managed to inscribe the keys with his memories before his demise. 

With Sofia in tow, Ezio visits Masyaf, where he finds Altair's corpse and the Piece of Eden that was in his possession. He then speaks directly with Desmond, learning that he's a direct conduit into his present-day self, and leaves his assassin tools behind.

Desmond then runs into another virtual figure, Jupiter, who explains that their society tried to use technology to save the planet, but somehow failed. A solar flare left massive damage on the Earth before, and another is coming. He finally learns the location of the vaults where he can stop the next coming flare, and snaps out of his coma. He finds Rebecca, Shaun and his father William waiting for him, and he explains he knows where the vaults are.

Assassin's Creed III (2012)

Taking place in an entirely new location with a new assassin, Connor, AC III twists the story even further.

Desmond and his team make their way to New York and open the server room with the help of the apple, and find a door requiring a key. Desmond passes out soon after and is put into the Animus, where he links first with Haytham Kenway and, eventually, his son Ratonhnhake:ton, who later becomes known as Connor.

At first, Kenway works as an Assassin, only to meet Connor's mother and birth a child, but he's soon revealed to be a spy for the Templars, recruiting the likes of Charles Lee and gaining the trust of the Mohawk tribe. 

Following the death of his mother, Connor learns the ways of the assassin from Achilles Davenport. He then springs into action, working with the Patriots and stopping various Templar plans throughout the American Revolution.

In the midst of this, Desmond wakes back up, working with his allies to recover power sources, including one possessed by Abstergo.

Back in the Animus, Connor confronts and kills Haytham after learning of his true roots. He then sets out after Lee – the man who was responsible for the death of his mother – who he successfully kills. He then finds an amulet, as well as his village ravaged soon after. Juno, in holographic form, explains he must bury it. 

In the modern day, Desmond finds the amulet, using it to open the inner temple door. A control sphere appears, and Juno explains to Desmond he must touch it. Minerva returns, explaining that if he does, he'll stop the solar flare, but unleash Juno, who may be an even bigger threat to the planet. The two argue back and forth about what should be done, but, eventually, Desmond opts to free Juno, killing himself in the process. As a result, the solar flare is stopped, but Juno explains that it is now "time to do her work."

Where will this tie in with Assassin's Creed IV: Black Flag?

Though we do a majority of the story will take place in the pirating waters – with Haytham's father Edward Kenway in the main role – it's not known who players will control in the modern day. Apparently, though, Abstergo will return, and somehow it will all tie in together. Juno is likely to appear again as well, ready to "do her work," as it were.

Assassin's Creed IV: Black Flag releases on October 29th for Xbox 360, PlayStation 3, Wii U and PC; November 15th for PlayStation 4; and November 22nd for Xbox One.