The Unanswered Question

"You said that he was in semi-control?" asked Ozpin.
"Actually, I got that from Lie Ren, but yes." replied Ruby.
Team RWBY and JNPR are sitting in Ozpin's office, discussing the incident that happened on the previous day. Lucifer isn't there because he is still recovering from once again releasing Neimo.
"Hmm...maybe he's getting the hang of this whole..." he pauses "...Half-Grimm usage." but he sounded unconvinced. Maybe even worried, though about what is unclear. "Anything else?"
"Yeah." says Weiss "He spoke."
"Excuse me?"
"I said Neimo spoke to us."
"What did he say?"
"He said, 'Tell Lucifer he owes me one.'"
"Owes him for what?"
"For saving my life." says Blake.
"Are you certain of that? Last time he came out he tried to kill you all." asks Ozpin
"Yes, but...I don't know. He was right behind me. He stopped an attack that was meant for me, and then he killed everyone that posed a threat to me. What happened to the dead White Fang, anyway?"
"You don't need to know" Neimo's rampage at the warehouse was covered up as a police raid gone wrong.
"One other thing" says Jaune "I'm not very sure myself if I'm right, but...Neimo...his Aura seemed somewhat less then it was the last time he was released. It may mean nothing, or maybe that as the cause of Neimo's..." he waved his hand around, as if finding the correct word for it "...decreased viciousness."
"I noticed it, too." says Lie "His Aura was down around twenty-eight percent from the last time he was released, though I don't know if it was that that influenced him, either."
No one was talking about how Neimo laughed like a psychopathic maniac after killing all the White Fang.
"Well" says Ozpin "That'll be all for now. If you have anything else to say, feel free to say it. I'll be here all day today. Dismissed." Both teams filed out the double doors.
Ozpin kept his peace about what was not said. He noticed how Blake said "but...", as if there were something else to him, something that says Neimo didn't do it for her sake, but whatever it was, either no one thought it important enough to be brought up, or they were protecting Neimo for something that he did or something that happened.
Ozpin wondered that, if they were protecting him, if it were a good thing - because he has gained real friends - or a bad thing - because whatever problem it was may manifest into something horrible.
He briefly entertained the thought that bringing in Lucifer, and Neimo with him, might turn out to be another of his mistakes, but he pushed the thought away, knowing that it was safer to keep him here rather than out there, on the streets, where there could be danger to innocent civilians and Lucifer either from Lucifer himself or whoever is trying to capture him.
But keeping Lucifer here with his students, apart from team RWBY and JNPR, and maybe Velvet, oblivious to his true nature, was that a bad thing? Would he find out too late? Would it matter?
Questions, questions, questions...so many questions..."Questions cost lives." murmured Ozpin "quote of a traitorous general, who lost faith in his cause due to questions asked." he sighed.
He hoped it wasn't anything terrible.

"This is terrible." says Ruby "What happened to him? He was laughing like he killed for fun, and was getting a real kick from all that White Fang."
"Why didn't we tell Ozpin, again?" asked Weiss.
"Because he may kick Lucifer out of here if we do." says Ruby.
"He won't" says Pyrrha "He won't throw Lucifer back out onto the street where he may be a danger to himself and others around him."
"However," says Lie "Ozpin won't trust Lucifer as much."
"Yeah..." says Weiss "I guess so..."
"We can only hope that this doesn't go too far." says Pyrrha "Besides that? Not much."
"But there is something else we can do?" asks Jaune.
"Maybe." says Pyrrha "Ask Lucifer how did he manage to decrease his Aura level."
But Lucifer is otherwise occupied at the moment.

- Here we go again...
Lucifer is once again in his mind, awaiting Neimo's arrival.
So he can kick my ass again, thinks Lucifer, and the thought echoes loudly through the landscape, causing his ears to ring painfully. 
Of course his thoughts were like boom boxes everywhere, this was his mind.
- Lucifer.
Turning, Lucifer once again sees Neimo.
- What?
- What did you do? I couldn't choose who I wanted to kill. Honestly, those animals were enough, but the cat-girl is still a life I would have otherwise taken.
- Which is why I wouldn't tell what is it I did, no matter what you do to me here.
Neimo growled, his bone-white fangs visible through the light-drowning Aura surrounding him.
- I should kill you.
- You won't. And you can't. Killing me would also kill you. You live in my mind, you work through my body. Killing me will also kill you. Besides, I won't let you.
Neimo scoffed.
- 'You won't let me'? Hah! You couldn't even recognize the insides of your own mind last time. What makes you think you have any power over me as long as you're here?
- Because...
Lucifer paused a moment before speaking.
- This is MY mind.

Lucifer awoke from the dream-state rather calmly, as if he were simply closing his eyes to rest them for a moment. He smiled to himself.
He had won his first battle against Neimo.