3. Darth Maul's Family
The Clone Wars does a great job revealing Maul's backstory, specifically his relationship with his family.
His mother is Talzin, a Dathomirian who was to be Darth Sidious' Sith apprentice, but Sidious instead kidnapped a young Maul and took him under his wing instead. Talzin later helps restore Maul's sanity and craft him some new legs, and even ends up sacrificing herself against Sidious to allow him to escape.
There's also Maul's brother Savage Opress, who became his apprentice during the Clone Wars and was ultimately murdered by Sidious.
While some might argue that this all humanises Maul far too much, it is nothing if not an interesting direction in which to take the character, and it's canon too.