Patience was never Nathan's strong suit. In fact, he would admit that it is one of his glaring flaws.
Which was why, when Nathan remembered that Sekirai would be getting his Evil Pieces soon, he did not think 'soon' translated to a year for devils, Nathan was frustrated beyond belief.
But then, on second thought, Nathan realized that it would be a good thing for him.
'I have time to train.'
He had time to get stronger; something that he gladly took advantage of.
Sekirai was not blessed with natural talents; whether it was in the field of demonic power, or in Power of Time.
No, Sekirai was painfully average. At least by pure devils' standards.
Nathan believed that Sekirai was talented, but not in comparison to others.
Issei, Rias, Sona, Seekvaira, you name it. They were all more talented than he was. Heck, even Diodora could be called talented in comparison to Sekirai.
But that was fine. Nathan was used to working with nothing. His job as an engineer often required him to do that. To him, having Sekirai's foundations was like finding an oasis in the middle of a desert.
Through the past months of his reincarnation, the majority of his days were focused on training, reserving as little time as possible for etiquette lessons and sleep.
Nathan preferred to have an organized schedule- as most people did. His time in training demonic power and Power of Time was spread as evenly as possible, although he did seldomly cut into one category's time, namely Power of Time, as he needed to catch up on his demonic power.
Sekirai's reserves was equivalent to a middle-class devil, even without training. While others, namely Rias and company, were born with reserves greater than that, Nathan was happy with Sekirai's natural reserves. Sekirai has also dabbled in his house traits, although his control over it was limited, from what Nathan could infer from his memories.
Which was why, currently, Nathan was attempting to use both demonic power and Power of Time at the same time.
"FUCK!", Nathan couldn't help but curse as he saw his two different energies fizzle out of existence.
For the past week, Nathan tried his hand at using both powers at the same time after realizing that when using one, he needed the other to compliment them.
Due to his limited time in training with his demonic power, Nathan needed time- too much time in his opinion, to form magic circles and cast spells.
On the contrary, when he used his Power of Time (PoT), he didn't have any real weapons to rain upon the enemies trapped in his barrier.
He could never use both at the same time- he figured that out from the past week's efforts. Hence, his current efforts were focused on using both. If, no, when he succeeds, he would be able to end a fight quickly. That way, his limited demonic reserves wouldn't matter.
Nathan took a deep breath and slowly exhaled, while mentally relaying commands to himself.
'Draw energy from the demonic reserves and imagine the spell.', was his first step. Through this, he was able to see the outline of a spell, specifically the fireball that he casted months earlier, shortly after his reincarnation.
'Now, draw upon the Power of Time. Create a barrier enough to cover a large tree. Slowing time in it.'
Through his second step, he realized a barrier that was enough to cover his desired object, in this case, a large tree.
Now, onto his third step, the reason behind his many failures.
Activate the fireball spell, and maintain the time barrier. When combined, the two proved to be a difficult task for Nathan, as he has to split his concentration equally.
If his concentration was a scale, then it would be tipped towards the demonic side of his power right now.
'No! Go back, focus on the barrier!, Nathan forcefully tore a portion of his attention away from the casting of the fireball, and he evenly distributed that attention back to his time barrier.
Good. The scale was even.
His brows creased intensely as he kept his concentration even between the two powers, both of which threatened to fizzle out of existence should he focus too much on one or the other.
The scale, the figure of his even distribution of concentration, was swaying back and forth on both sides, but eventually, it calmed down. It was a sign of his concentration being even.
'CAST THE FIREBALL!'
Nathan's mental command prodded the magic circle to fire (pun intended) the fireball, and it flew as straight as an arrow, with moderate speed, towards the tree that he casted the time barrier on.
At the last second, Nathan dispelled the time barrier willingly, for the sake of the fireball not being slowed down, and it worked. The fireball impacted the tree, immediately dispersing itself through it, starting a fire.
Nathan smiled in satisfaction. He had done it.
Of course, Nathan didn't let the satisfaction from his success take his attention away from creating a water spell to get rid of the spreading fire, as that was what he did immediately after.
'At this rate, by the end of the year, I should be able to win against the average Pillar heir.'
Nathan analyzed his growth over the 3 months that has passed since his reincarnation, and he was confident that he would be able to win against the heir of a noble family, should they laze around and not train.
'Alright, back to work.'
Nathan lifted his arms, a green energy shining from one, and a black one shining from the other.
Time to try this all over again.
At least he has experience now.
Nathan realized that he was eleven, turning twelve when he saw a banner flying in the guest hall, saying, 'Happy 12th Birthday, Sekirai!'
He dumbfoundedly stared at it, only to be shaken out of his state as his mother, Alisa, tapped on his shoulder and said, "Do you like it?"
Nathan nodded, "Yeah. It's great."
Alisa smiled in happiness, before turning around and walking away, her blonde hair swaying with her hips alluringly. "There's more preparation for us to do. After all, this is your coming of age party."
"You have to start preparing this early? There's still 9 months left."
His mom paused, considering the question. "We'll be inviting the Pillar families. It's best to be prepared before the time comes. As humans would say, it's better to be safe than sorry."
"Alright. Good luck then."
Nathan decided to head for his room, as there was nothing to do, because he had finished his training earlier.
It was time for him to take a look at his collection.
Collection of materials, that is.
The Agares family was fairly rich, having many sources of income. The major ones are the city of Agreas, which was a flying island, and a popular tourist resort. The other one was Auros, a town located in Agares territory and is said to have the best agriculture product in the Underworld. The combination of the two made for a large part of income for the Agares family.
As the head of the branch family, Sekezer Agares, was quite rich, and by extension, his son, Sekizer Agares, received a lot of money for allowance.
Allowance that was never used by Sekirai properly. But fear not, Nathan will put the allowance to proper use.
'I'll need a weapon.', Nathan thought to himself. 'The question is, what kind of weapon?'
Nathan considered his options. He instantly eliminated the sword. He had no close combat ability, and his very limited self-discipline won't allow him to train for a long time. At most, he would do physical exercises. By extension, all melee weapons were eliminated.
Now, he went onto the ranged category. As a former resident of Earth, his first thought was; a gun.
'A gun would do little to stop a Satan class devil coming at me…', Nathan considered its flaws. 'But then again, it IS the easiest weapon for me to use, by far.', and its strengths. 'Yeah, a gun is good. Although his mind was set on the gun, he didn't neglect the other options, such as magic and archery.
'Archery would be good… but it's like a gun. But weaker. At least for my level. As for magic? It's a valid option, but that would have to wait until my reserves grow.'
'Now… where would I get a gun?'
A/N: I skipped 3 months of his reincarnation because all of it would be him training, with very little adjusting.