After Nero returned, he began to retrain his powers to use his shadows and his few dark powers without completely depleting his physical and magical energy resources. He reached to the point of using his shadows without any problems, but the darkness still made his body feel depleted even if he now can use it more properly and even try to use as some ofensive moves in critical situations. He know he still is a mid-class devil in terms of strenght but with the power of darkness he is able to use attacks capable to reach the level of an high-class devil and harm stronger enemies.
When he ended his train he decided to act a little bit out of his ordinary and try to have some action to test his skills. When he was planning to leave the silver haired maid saw him with a sword and questioned.
"Are you going out, young master Nero?"
"Ah, first you don't need to call me young master or master, you are basically my aunt if I consider your relation with my mother. To your question, yes I am. But not alone, if possible, I hope you can accompany me to Naberius territory."
Hearing Nero talking about the Naberius family again, Grayfia remained expressionless but in her calm eyes there were traces of a little bit of worry.
"The Naberius family... as you said before the reason might be the transcendental experiment, am I right?"
"I can see from Sirzech's previous interaction with me that he does not doubt my sincerity, but this matter is too important for him to discuss with the other devil kings and the devil's council and these actions may attract Rizevim's attention. So I plan to deal with it more cautiosly without making it become a open problem."
"Nero, they will not create problem discuss..."
"Don't say it Grayfia, the new devil king faction is not very different from the old faction. Since it is a faction, it is impossible for anyone to stand alone. Especially now that the old devil king faction is no longer the biggest enemy, the diferent opinions within the reformist faction will only increase as they will lead to everyone there trying to get their personal interest. Sirzechs himself may have believed me, but he know this kind of matter need to be dealt seriously so he cannot act directly because he is the current Lucifer and he have big responsabilities."
"Then you plan to..." Grayfia start speaking subconsciously, but she stops because she already understood his plan.
Nero smile and say. "My surname is Lucifer, but I am not the devil king Lucifer right now, and I am a member of the old devil king faction. No matter what I do, it will only be counted as the action of the head of the old devils king faction. Those guys on the new faction may have the guts to point fingers and order Sirzechs because he have obligations with them, but will they have the courage to come to me if this means to provoke the entire old faction?"
"Your logic is correct, they will not complain, at least not in the bright side."
"It doesn't matter to me how much those old guys scold and curse me when they are somewhere I can't even listen to them. Anyway, as long as a live and do what I think is right, then I am fine. How the others judge me, I dont care."
After saying this Nero go out of his house and start his travel to the Naberius family.
"Let's go Grayfia." He walks away with courage.
"Okay." She follow him quietly and observing his plans with interest even if her face is still expressionless.
When they reach the Naberius territory Nero explain his plan to Grayfia. He will infiltrate the territory while she just follow him to be testify his actions and the secrets from the Naberius family. After the discussion, they sneak into the mansion, they realize complete chaos taking place in the place with many dead demons and broken experiments, but soon they find a young white haired girl who is being dragged by three high level devils to some laboratory.
"Grayfia we need to save that kid. Lets go now, I will take down the one holding the girl and you attack the others" He says as he focuses his darkness on his fingertip to make a single attack to directly kill the enemy and Grayfia immediatly subdue knoking out the other two. So they go talk with the girl.
"Hey girl whats your name, what are you doing here?" Nero asks to the girl who is clearly crying.
"My name is Shirone, my elder sister told me to run away, but she is still fighting inside that place." Says the girl as she trembles with fear, but strangely has a forced expressionless face.
"Could you tell me more about your sister?" Nero tries to reasure her.
"She looks like a older version of me, she has black hair and and hazel-gold eyes with cat-like pupil.She is fighting against the devils inside of the laboraty." Says Shirone.
"Don't worry Shirone, I will save your sister trust me." Nero gives her a confident smile.
"Young master Nero, I don't think entering the Naberius family without previous preparation is a good plan." Grayfia suggest with some concern.
"I know it will not be a good idea and I might get in trouble, but Grayfia, you must take the girl out of here and call Sirzechs. I will enter this place to find this girl's sister, and before you ask no I won't trade the functions with you. I know you are stronger but you are the only one here capable to bring Sirzechs and I am from the same family from Rivezim so I can stall the Naberius suspect from more time. Find me later." He directly enter his own shadow to move inside the underground from the facilitie.
While moving from the shadows Nero finds a black haired girl who reminds him of Shirone and clearly is Kuroka if Shirone description and his small knowledge adquired from the novels is not wrong. She is fighting the head of Naberius family who aparently is having advantage in the combat while the girl is showing signs of exhaustion.
"Keep attacking Kuroka!" Nero say as he start to move through his shadow to get a chance to hold the high-level devil for time enough to Kuroka hit him.
Kuroka loses concentration when she heard his voice and is hit by a devastating blow. She staggered back, and goes to attack her enemy again but this time Nero use his shadows to bind him in place and let her punch him with all her might.