Make Maul an ex-sith lord. He tried his hand at taking over the galaxy, his master betrayed him and his brother died and now his master is ruling the galaxy but with a new apprentice and Maul knows he will never be taken back and that makes him angry and hateful. So Maul has hung up the tittle of sith lord and has dropped the name Darth and is just called "Maul" now. And he is still hunting Jedi and stuff because he has no love for jedi but he is also attacking the empire because his master betrayed him. And he is like this phantom warrior that kind of just shows up places and wrecks house.
He doesn't even need a death. Why does every starwars character need a death? why cant they just kind of walk away and disappear forever?
Needless to say none of that is going to happen and Darth Maul is going to die a stupid death because **** creative story writing.