So, let's just get the super obvious out of the way. Yes, that was the character formerly known as Darth Maul you saw in hologram form at the end of Solo: A Star Wars Story. The villainous character was first introduced in 1999's The Phantom Menace.
Solo: A Star Wars Story concluded with Maul appearing via hologram to Qi'ra, a former love of Han Solo who ended up working for Crimson Dawn. After the death of the syndicate's more public face, Dryden Vos, Maul asked Qi'ra to join him on Dathomir and claimed they would be working together more closely.
That type of attitude was why Qi'ra rejected Han in Solo. After killing Dryden Vos, she became the public head of Crimson Dawn and its dark dealings. That meant that she had a dark future as Maul's underling, which is why she rejected Han.
A new Star Wars theory suggests Rey is the daughter of Han Solo and Qi'ra, but there's plenty of evidence in the existing franchise canon to debunk it. The young scavenger's heritage was one of the biggest lingering questions following The Force Awakens, and audiences had to wait two years for the answer.
Qi'ra told Solo she would be right behind him, but as Solo left, she instead took Vos' ring, and used it to contact Maul, the actual leader of Crimson Dawn, informing him that Vos had failed to obtain the coaxium.
Han Solo's death in The Force Awakens (2015) came about when writer/director J. J. Abrams felt the character was not evolving or contributing to the story's development; he believed that Kylo Ren killing his own father would give him a chance to develop into a worthy successor for Darth Vader.
Kylo Ren dies on Kef Bir (the ocean moon of Endor) shortly after Rey deals a mortal wound during a lightsaber duel on the wreckage of the second Death Star. Though Rey Force-heals him, saving his life physically, this blow, coupled with the memory of his mother and father, destroys the man known as “Kylo Ren” forever.
Thought dead, Darth Maul survived his injuries by focusing on his hatred of Obi-Wan Kenobi, the Jedi who cut him in half. His shattered body was dumped amid the refuse of the junk planet Lotho Minor, where the once deadly warrior fell into madness, staying alive on a diet of vermin.
As the son of Mother Talzin, the Zabrak male was taken from a young age by Sidious to act as his impressionable apprentice. The boy was raised as Darth Maul, a name he carried throughout his life. In Legends, it was insinuated that he was born "Maul" before attaining the honor of the "Darth" title.
Chastened by his former Master on the principle of the Rule of Two, Maul abandoned his claim to the mantle of the Sith, focusing instead on building an empire of his own—the Crimson Dawn—by controlling the criminal underworld.
Sidious revealed to Maul that he did not intend to kill his former apprentice, as he still had use for Maul; it was Sidious' hope that Maul would lead the Sith to Mother Talzin, Maul's mother and the leader of the Nightsisters, so she could be eliminated as a potential threat to the eventual Sith rule of the galaxy.
Maul most likely knew Sidious' double role as Palpatine and Sidious when he served as Palpatine's apprentice. He definitely knew about Palpatine's goal of creating a galactic empire ruled by the Sith. Maul knows that Sidious is the Emperor.
Why is Darth Maul red and not yellow? Darth Maul was originally born a black-skinned Nightbrother, but was later stripped of his markings and given red-skinned Sith tattoos by Darth Sidious. His eyes were also turned yellow with red rims, either due to his touch of the dark side or the eyes he was born with.
Affiliation(s) Zayne Skywalker, a Human male Force-sensitive, was the son of Ben Solo and Rey Palpatine, a dyad in the force as the great grandson of the Chosen One and the son of powerful force wielders, who later becomes a legendary warrior and hero for the galaxy in the decades after the Battle of Exegol.
During the battle, Anakin, who had been known as the Sith Lord Darth Vader, was redeemed by Luke and brought balance to the Force. However, the redemption cost Anakin his life, having been mortally wounded by the Emperor, Darth Sidious, while killing his former Master.
But this is actually a very sad reason because it actually had the opposite effect, and he deeply regretted his decision to kill his father and it haunted him for the rest of the trilogy. Also, Han was telling him that Snoke was using him, but one of the reasons he killed him was to impress Snoke.
Ben Solo, son of Han Solo and Leia Organa, was once a promising Jedi apprentice taught by his uncle Luke Skywalker. But under the influence of the mysterious Snoke, Ben rejected Luke's teachings and destroyed his temple, leaving with several of his uncle's students and killing the rest.
Darth Vader's true identity as Anakin Skywalker was a highly guarded secret, known only to a select few individuals including Palpatine, Obi-Wan Kenobi, Luke, Han, Leia, R2-D2, C-3PO, Master Yoda, Bail Organa, Ahsoka Tano, Darth Maul, Grand Moff Tarkin, Grand Admiral Thrawn, Jocasta Nu, Ferren Barr, Verla, Reva, ...
Following Qui-Gon's death by Maul's hand on Naboo, Dooku visited Palpatine in distress about his apprentice's death, hoping to have one day made Jinn an ally while also directly stating he knew of Maul's existence.
Maul's appearance in “Solo” suggests there's still more to his story, though. Crimson Dawn is described as being an extremely powerful criminal syndicate that works both within the Empire and against it. That means he's clearly a force in the galaxy.
