Originally posted by Enyalus
His final test to becoming a Sith Lord was that he had want to kill his master (Sidious) - which he accomplishes.
From the Ultimate Visual Guide, page 34.
"Unlike previous Sith apprentices, Maul has no ambition to overthrow his Master."
"Darth Sidious treats Darth Maul as neither friend nor accomplice, but a tool who will obey his every order."
Maul, in Shadow Hunter, muses that if Darth Sidious ordered Maul to kill himself, he'd do it.
What specifically states that he was not going to be his successor? I have NEC and JvS.
tNEC says that Maul was merely a temporary assassin until Sidious could acquire Skywalker. JvS says that Palpatine gave Maul dreams of razing the Jedi Temple, knowing full well that it would never happen, and forsaw his death at Naboo but didn't inform Maul, knowing that he'd acquire a stronger apprentice.
"Blinded by pride, Dooku has failed to grasp that, like Darth Maul before him, he is little more than a placeholder for the apprentice Sidious has sought from the beginning: Skywalker himself."
-- Complete Visual Guide, page 139.