Recent Star Wars trailers have been masterpieces of tickling fanboy excitement while steering almost perversely clear of spoilers. That’s certainly true of the latest glimpse of The Rise of Skywalker – the ninth film in the series – which landed online on Monday, having premiered at Disney’s D23 Expo over the weekend.

It’s the climactic shot of the new clip that has Twitter fingers twitching. The final moments of the trailer feature Daisy Ridley’s heroic Rey clad in distinctly Sith-like robes and wielding a red lightsaber. This is almost certainly a piece of misdirection from director JJ Abrams – known for loving “mystery box” plots even more than he loves blinding lens flare – rather than a grand heel-turn for the franchise’s new leading lady. But it’s the lightsaber itself that is particularly exciting. It’s a dual-bladed weapon, with Ridley’s character snapping the two parallel halves together to form a double-ended staff akin to the one wielded by Darth Maul in the widely derided prequel The Phantom Menace.

Rey’s new weapon – even if it proves to be a temporary addition to her arsenal – is the latest unconventional lightsaber to appear in Star Wars. Kylo Ren’s flickering home-made saber, complete with crossguard, caused a stir when it served as a money shot in the first trailer for The Force Awakens, and has proven to be the villain’s weapon of choice ever since.

When the lightsaber was first introduced to audiences in George Lucas’s original movie, it was described by Alec Guinness’s Jedi master Obi-Wan Kenobi as “an elegant weapon for a more civilised age”, as opposed to the “clumsy and random” blasters used by those not deemed worthy enough to join their slightly odd cult. The Jedi/Sith binary is one bound up in tradition and so the idea of a weapon of pure light – which can connote either good or evil depending on where it sits on the colour spectrum – fits the theme perfectly. From the earliest moments of the Star Wars universe, a clear link has been drawn between lightsabers and the characters wielding them.

That link makes the new trilogy’s lightsaber innovations even more interesting. Kylo Ren’s weapon is explicitly tied to the immature, petulant bravado that leads him to regularly trash his surroundings in an adolescent strop. The saber was constructed by Ren himself and is evidently an imperfect creation, with its beam of light filled with static crackle – a hastily assembled tribute to the weapon of his idol and grandfather, Darth Vader. It’s the equivalent of a 90s grunge kid recording a tinny version of Smells Like Teen Spirit and thinking he’s Kurt Cobain.

Facebook Twitter Pinterest Kylo Ren brandishes his DIY lightsaber. Photograph: Allstar/Disney/Lucasfilm

It is also the only lightsaber to feature a crossguard. There is a technical explanation for the innovation, as fans of deep-dive Lucas lore will know: the damaged kyber crystal in the handle of the device would overload the blade if it were not vented through the ancillary beams. However, perhaps the immature Ren – an avatar for fragile masculinity – also just thought it looked cool.

So what does Rey’s new lightsaber tell us about her? Intricate fan theories already abound that posit Rey and Kylo Ren as two sides of the same proverbial coin. The idea of “bringing balance to the force” has been a constant theme throughout the series, and it’s that which is symbolised by Rey’s lightsaber – two equal, parallel forces uniting to form something completely balanced, like Thanos’s double-sided weapon in Avengers: Endgame.

One explanation for the incongruous clip of Rey channelling her goth side is that it’s some sort of dream sequence. But it would seem bizarre for Abrams and his team to create such an innovative new lightsaber design for the sake of a single throwaway moment. There may be more going on here than meets the eye.

Or maybe Disney just wants something new to fill the shelves of toy shops.