What happened to Darth Maul in other Star Wars stories?
For a guy who got cut in half, Darth Maul has been very, very busy. Even a cursory reading of the character's Wookieepedia page reveals that Maul has been a major player in countless Star Wars branded narratives since he made his first appearance in 1999. Like Boba Fett, another cool-looking character introduced with little backstory in a Star Wars film and then quickly killed off, he's long been a source of fan obsession and a reliable figure for writers to find inspiration in. His secretive quality in the movies allows cartoons, novels, comics, and video games to fill in the gaps with ease.
For our purposes, the two most important series for understanding Maul are The Clone Wars, which aired on the Cartoon Network from 2008 to 2013, and Star Wars Rebels, which currently airs on Disney XD. In these series, we find out that Maul didn't actually bite the dust when Kenobi defeated him at the end of The Phantom Menace; instead, using his Force powers, Maul made his way to a trash container and eventually found his way to a trash planet, Lotho Minor. On this planet, he created some spider-like junkyard legs for himself and eventually received newer robotic legs during a creepy ceremony you can watch here. The procedure is actually performed by his mother, an extremely powerful Force witch named Talzin. Yikes.
From there, Maul goes on to battle Kenobi multiple times and engages in a wide range of sinister behavior that's fun to read about in recap form but not exactly pertinent to how the hell he ends up talking to Emilia Clarke in Solo. It's unclear exactly how the Crimson Dawn fits into the larger world of the new Disney Star Wars films -- in The Clone Wars, Maul leads a bad guy group known as The Shadow Collective -- but it does feel worth noting that in the video from Star Wars Rebels you'll find above, Darth Maul does, again, get killed by Kenobi on Tatooine. In that version, his death appears to be permanent. But, for Darth Maul, death is a slippery concept.