Warning! MAJOR SPOILERS for Solo: A Star Wars Story ahead!
Solo: A Star Wars Story features a major cameo from a popular Star Wars character that no one saw coming - Darth Maul! For years it was thought the Sith Lord died when Obi-Wan Kenobi cuts him in half and his bisected body tumbles down that reactor shaft on Naboo - yet Maul lives, but how?
First introduced in Episode I: The Phantom Menace, Darth Maul is the apprentice of Darth Sidious (AKA the soon-to-be Emperor Palpatine) and strikes an imposing figure with his red skin, black tattoos, horns, and billowing, black robes. Portrayed by actor and martial artist, Ray Park (with Peter Serafinowicz voicing his three lines of dialogue), Maul's big moment in that film comes when he duels with Qui-Gon Jinn and Kenobi. The three-way duel in The Phantom Menace's final act is for many the biggest highlight of the film and it's thanks in large part to Maul's flashy, acrobatic fighting style and his now iconic double-bladed lightsaber (not too mention John William's fantastic scoring of "Duel of the Fates").
Maul kills Qui-Gon in that duel, but Kenobi proves to be more of a challenge, eventually besting and halving Maul. And yet, Maul didn't die as Episode I would have viewers believe. Instead, Maul lives and in a string of episodes from the animated series, Star Wars: The Clone Wars, it is revealed how he survives and what he's been doing since that fateful duel on Naboo.
Darth Maul's Survival Explained
Being severed in half by a lightsaber is a serious injury, make no mistake, but due to the very nature of lightsabers, any wound is cauterized just as quickly as it happens. So in Maul's case, though he was cut clear through, most if not all of his vital organs stayed within his upper half. Beyond that, Maul's intense hatred for the Jedi - and Kenobi in particular - fuelled his will to survive, enabling him to use The Force to pull himself into an air vent and eventually land in a trash container.
Maul's mangled body was dumped on the junk planet, Lotho Minor, where he remained for twelve years. There, Maul constructs for himself a set of spider legs to replace those he lost while surviving on whatever local vermin he can find. In time, the loneliness of exile drives Maul mad, but he never loses sight of what he wants most of all - revenge on Kenobi.
Maul is eventually sought out by his brother, Savage Opress, who is sent by the Mother Talzin of the Nightsisters - a coven of Force-wielding witches from Maul's home planet of Dathomir - to find Maul and return with him. Upon doing so, Talzin employs her magic to heal Maul's mind and give him a new pair of cybernetic legs. With his mind and body restored, Maul takes Savage on as his apprentice and the two embark on a mission to destroy both the Jedi and the Sith.
Over the course of Star Wars: The Clone Wars, Maul had multiple encounters with Kenobi as well as Sidious and his new apprentice, Darth Tyranus/Count Dooku. He formed an alliance with the Mandalorian terrorist group, Death Watch, and with their leader, Pre Vizla, built a coalition of criminal organizations called the Shadow Collective. Maul even comes to rule Mandalore for a period before he's overthrown, after which he escapes into exile once again. Maul resurfaced during Star Wars Rebels where he tries to corrupt the young Jedi, Ezra Bridger and later has one final duel with his greatest adversary, Kenobi.
Maul's cameo in Solo: A Star Wars Story comes between The Clone Wars and Rebels in the Star Wars timeline, meaning there's a whole new chapter to his story being added. Maul is again building an alliance of criminals, and Lucasfilm is continuing to develop the character long after his supposed "death".