Star Wars saga

The Star Wars Saga, also known as the Episodic Films or Skywalker Saga, is an unofficial term meant to designate the "primary" Star Wars movies from secondary and non-canon movies. It presently consists of a Trilogy of trilogies: The Original Trilogy, The Prequel Trilogy, and The Sequel Trilogy. Together, they form one large, over-six-decades-spanning narrative (32 BBY - 34+ ABY).

The term Saga is also used to contrast the main stories from the Anthology one-offs, the animated Clone Wars film, future non-Saga series, trilogies, and other possible movies.

Characteristics
The Saga movies all contain the following characteristics (with possible exceptions noted):

Episode Titles
The-as-of-present 8 released Saga Films begin their designation with "Episode" followed by their chronological order displayed as a roman numeral. It is reasonable to expect that Episode IX will follow this same practice.

Of note, the debut episode, A New Hope, was released simply as Star Wars, as there was not yet clarity or green light for a sequel. Beginning with its April 10, 1981 re-release, (11 months after The Empire Strikes Back) it was renamed to Star Wars: Episode IV A New Hope.

Canon
All Saga Films are canon.

Prior to the Disney reboot of the Extended Universe, the then six Saga Films (Episodes I-VI) were the highest form of canon, known as G-Canon (or George Lucas Canon).

In defining the reboot, almost everything that was not a Saga Film became Legends; three exceptions included: The Clone Wars TV Series, its introductory movie, and Darth Maul—Son of Dathomir (a Dark Horse a 4-issue comic book mini-series based on unproduced The Clone Wars Season 7 scripts).

Going forward, most (if not all) Disney-created Star Wars content will be canon, especially the Saga's possible conclusion trilogy of Episodes VII-IX.

Opening Crawls
All of the Saga Films begin with the blue text "A long time ago in a galaxy far, far away…" card which is then immediately followed-by the Star Wars logo and the slanted, yellow-text-on-starfield summaries of immediately preceeding off-screen action. While the typefaces vary slightly, these all follow the same overall general format.

These crawls were inspired by the Flash Gordon serials of George Lucas' childhood. At present, the Anthology and TV Movies do not contain these, nor are they expected to.

The Skywalker Lineage
While possibly not first intended as such, the movies, at minimum, evolved into tracing Clan Skywalker through all 9 arcs:

The Original Trilogy (Real-World: 1977 - 1983; In-Universe: 0 BBY - 4 ABY) focuses on protagonist Luke Skywalker, his unknown-to-him sister Princess Leia, and the reveal and redemption of their father, antagonist and former Jedi-turned-Sith Lord, Darth Vader/Anakin Skywalker.

The Prequel Trilogy (Real-World: 1999 - 2005; In-Universe 32 BBY - 19 BBY) focuses on protagonist Anakin Skywalker as he matures from 10-year-old Tatooine slave child to Padawan to Clone Wars General and galaxy-defending Jedi Knight. His mother, Shmi Skywalker, features significantly in Episode I, also as a slave, with a return cameo in Episode II, in-which her later-and-surprise marriage provides Anakin with a previously unknown step-father and step-brother (who retro-actively appears in Episode IV as Luke's uncle).

The Sequel Trilogy (Real-World: 2015 - 2019; In-Universe: 34 ABY - ?? ABY) focuses on the next generation, with special attention to antagonist Kylo Ren/Ben Solo, the bloodline and grandson of Anakin Skywalker, through his mother, General Leia Organa, initially Jedi-trained by his uncle, Luke Skywalker. Kylo survives Episode VIII and should be seen in the conclusion of Episode IX.

The Force, Orders, and Wielders
Because in-universe it binds and surrounds and penetrates all things, it could be said The Force is present in all Star Wars movies and media, not simply the Saga Films. However, there is an increased importance and prominence on the The Force in Saga Films and those who wield it: The Jedi Order, The Sith Order, and other individuals who attempt to study, learn and use it, usually under a mentor or master, in the absence of these Orders, such as Luke, Leia, Maz, Kylo Ren and Rey.

Galaxy-Wide Politics
There are typically major forces at work, representing governments, would-be-governments and groups fighting on behalf of governments, sometimes involving trade routes. The major divisions in each time period are as follows:

The Prequel Trilogy: The Galactic Republic vs The Confederacy of Independent Systems, as fought for by Jedi/Clones/Gungans vs Battle Droids/Geonosians/Sith

The Original Trilogy: The Alliance to Restore the Republic vs The Galactic Empire, as fought for by Rebels vs Imperial Military/Troopers

The Sequel Trilogy: The New Republic vs The First Order, as fought for by The Resistance vs First Order Military

Monomyth
The Trilogies follow Joseph Campbell's concept of Monomyth, or, "The Hero's Journey" Cycle, as Lucas studied Campbell's The Hero with a Thousand Faces and more while composing his universe.

"Plans"
George Lucas has changed the "planned" number of Saga Films from interview-to-interview over the years (with potentially as many as twelve as far back as 1978). After Disney acquired Lucasfilm in 2012, their "announced" Saga Films presently rests at a total of 9, as they develop more television shows, web series, Anthology Films, other films and trilogies.