Like the rest of his kin, Maul was subjected, shortly after birth, to an initiation ritual during which he was immersed in a "magic" oily bath, and covered head to toe in black and red tattoos. Later stripped of his black Nightbrother markings, Maul was left solely red-skinned.
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.
He felt the slash of saber after saber as he felt the death of his Sith brethren. His Sith training made Maul long for revenge against the Jedi Order, which had defeated the Sith a millennium earlier. With his master, Darth Maul hoped to destroy the Jedi and restore the Sith to galactic power.
His entire body had been garishly and ceremonially tattooed in red and black pigments by his mother when he was less than a standard year of age (before he was taken by Sidious), symbols which showed his Nightbrother heritage.
Zabrak Species COMPLETE Breakdown (Iridonian & Dathomirian)
Why was Maul killed so easily?
Maul's skills, on the other hand, became stagnant as he spent the last few decades of his life keeping himself alive and plotting schemes. Given this, it makes sense Obi-Wan quickly defeated Maul in their final duel in Star Wars Rebels.
Regardless, based on the season 7 of The Clone Wars, and the fact that Darth Maul was aware of Anakin Skywalker's future and his role as the Chosen One, it is very likely that Darth Maul indeed feared Darth Vader to some extent, and preferred to avoid a direct confrontation with him, at least, on his own.
Maul actually was his Sith name. In the Rebels tv series, Maul says to another character that he once had a real name, but he has long since forgotten it. Palpatine took Maul from his mother and gave him his Sith name as an infant. His real name is lost to time.
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.
Later stripped of his black Nightbrother markings, Maul was left solely red-skinned. Agonizing Sith tattoos were applied personally by Darth Sidious in an attempt to cleanse Maul's mind as well as demonstrating Maul's complete dedication to the dark side.
Maul shows signs of Antisocial Personality Disorder and Narcissistic Personality Disorder that were probably caused by a mix of genetics and circumstances.
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.
Darth Maul had yellow eyes, but Star Wars: Darth Maul - Son of Dathomir by Jeremy Barlow and Juan Frigeri shows that this was his natural eye color, like many other Nightbrothers. Being a Sith may have intensified the color of Maul's eyes over time, but his natural color makes it hard to know.
This detail wasn't planned by Lucas and his team, nor it has some meaning connected to the Sith, and was more of a “happy accident”. Ray Park, who played Maul in The Phantom Menace, has that piercing and forgot to take it off before sitting down to be transformed into Maul.
Darth Maul is considered to be a male Dathomirian Zabrak, and lived during the waning years of the Galactic Republic. His mother, Talzin, gave him up at a young age to Darth Sidious because she wanted her son to escape the life of a Nightbrother.
Even though Kylo Ren uses a red lightsaber, harnesses the dark side of the Force, and wears a cape, he is not a Sith. Because of that, he can never hold the title of Darth. Instead, he was just a chaotic mess of the dark side (until he eventually found his way back to the light).
As far as I know, there is no Canon date of birth for Maul, but in Legends, he was born in 54 BBY. In canon, Maul was killed by Obi-Wan Kenobi on Tatooine during the year 2 BBY. If we use the Legends year of birth, then Maul would have been 52 years old when he died.
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.
Darth was a Sith title given as both a name and title to the Sith Lords, an order of Force-sensitives who channeled their power through the dark side of the Force. The title, which roughly translated to "Dark Lord," was part of a Sith Lord's mantle, preceding a moniker that replaced the Sith Lord's original name.
Serving as a defining moment on the same level as Luke Skywalker's vision in the caves of Dagobah, Darth Maul's surreal time as a Jedi would serve to cement his beliefs that the Jedi Order had to be exterminated at all costs.
The strongest among the Exiles, Ajunta Pall, became the first to hold the title Dark Lord of the Sith. His contemporaries, such as Karness Muur and XoXaan, became Sith Lords. The human Dark Jedi interbred with the Sith species, who also had an affinity for the Dark Side. They would become the original Sith Empire.
Star Wars Rebels lead creator Dave Filoni even admitted that Maul and Vader were meant to have a fight, but he felt it would take away from the battle with Ahsoka. But as things stand, Star Wars not only lacks a fight between Vader and Maul, but the two have never even spoken to each other.
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, ...
