Jack under the guidance of Apophis, didn't Boost past three times for the moment for a good reason. As Apophis said, it wasn't his natural power so it was rough using it and he wanted to adapt a bit more to it.
The second issue was that since Apophis was fueling the Boost, it was less stable than the Boosted Gear. That was why Apophis set a limit of three to five as he and Jack would need to adapt to this stolen power.
The third reason was even if he could Boost to 4 times 16 times his base Mana would be quite noticeable since he didn't have good control yet. Since he had taken in his other selve Mana, he had nearly Ultimate Class Levels of Mana.
Instead, he merely sat himself down on his bed and used the increased Brain Power to take control of his Mana. According to Apophis, Jack, and the other Jack were born with higher-than-average Mana.
It got enhanced when they fused, and it was a lot of Mana, but with the Abyssal Eclipse Gear, his reserves would grow as long as he lived. With the guidance of Apophis, he carefully circulated his Mana after rousing it up.
Doing so would allow his body to begin to adapt and evolve under the influence of Magic. He was also instructed to hold the Boosted effect for as long as possible which happened to be around 12 minutes.
For his first time doing that, that was quite impressive. However, when he lost the effect, he began to feel hungry by increasing his Physical Attributes by a factor of eight including his recovery speed and metabolism.
Already he had fully recovered from his concussion and his skull fracture was fully healed. He was exhausted though so he fell asleep to allow himself to recover. When he woke up the next day he felt better than he ever had, just very hungry.
"I am starving."
[By Boosting three times, you increase your recovery and metabolism by eight so of course you are hungry. That is how you recovered so fast from a skull fracture and it will help you when you train in the future. Plus, now your magic is stimulated. Can you call on it?]
He focused deep inside his body and he quickly found his mana no longer stagnant. It was flowing through his body, enhancing him and making him stronger. He focused on his body and he focused on his right arm and felt it flow into the limb.
[Good, you have potential indeed. I will teach you what you can do later, for now, go eat. You will need it and don't tell your parents about me.]
"Of course, I won't tell them. I am not dumb."
Jack got out of bed to go to the kitchen as he could already smell his Mom cooking a good American Breakfast. When he walked into the living room his parents looked over at him. His Father in particular got up from the table.
"How are you feeling, son?"
His dad gently placed a hand on his shoulder so he looked up at his Dad with a small smile. His Dad was one of his favorite people because everyone was afraid of him. Plus, his Dad was huge as he was 6'8 and one of the smartest people he knew.
"I feel better, Dad."
Jack Sir smiled as he led him to the table.
"I am glad to hear it, you are going to stay home a few more days until we are sure you are ok. Your Mother will be checking in on you while I am at work. Later I think your friend will come check on you.
You did give her quite a scare."
Now sitting down he asked about her.
"How is Aya? I am sure seeing what happened would be quite scary."
His Mother from the look of her face was worried.
"She was crying and screaming that she didn't want you to die. That girl was inconsolable thinking she just saw you die. I think she will want to come to check on you later to see if you are ok. Just no more going outside for at least a week. Who knows if you pass out in the snow."
His Father agreed with his Mother as it was a really good thing he was with her when he hit his head.
"I agree. This was bad enough, but if you were not with her you could have died."
After feeling bad about putting not just his parents through a scare, but his only friend in Japan he would be more careful.
"Ok."
His Mother smiled as she walked over and placed a plate in front of him. It was pancakes with chocolate chips, bacon, hashbrowns, and eggs. She smiled as she kissed him on the forehead.
"Eat up. I know how you love this."
"Thank you, Mom."
While he started eating his Mother also placed a plate for her husband along with a cup of coffee. She liked cooking some new dishes from Japan, but sometimes something nostalgic was better.
She also sat herself down, but she didn't eat nearly as much as her son or husband. Now that he thought about it his Mom was tall too as she was 6 feet tall(183 CM). Once breakfast was over, Jack Sir left for work while Esmeralda, his Mother let him relax in the living room by watching TV.
What came on was Dragon So Ball, but with the memories of his other self, it was lame compared to Dragon Ball in that other world. He still watched it as some of it could be fun. As he watched the TV Apophis began to speak to him as he could see Jack using subtitles.
[You know, when you get a chance you could make use of the increased thought speed of Boosting to get a handle on Japanese. Using it more would give me more chances to adapt to it and it will help you too. It could be useful in the future.]
That did sound like a good idea.
'Maybe. If my other self memories are to be believed, humans cast magic through calculations. By Boosting a lot, maybe four times, I will think 16 times faster. I will be able to study not just Japanese, but Math well.'
[Not a bad idea, through that you will cut your research speed into magic down a whole lot. While human magic isn't as easy to use as Devil Magic which is based on intent and imagination it is far more versatile. Unless you are planning to be a Devil?
The other Jack didn't not out of human pride or anything, he just was confident in himself.]
Being a Devil didn't interest him as he had another race he wanted to become.
'Can I instead become a Fallen Angel? Maybe if we can meet Azazel somehow, we can have him turn me into a Fallen Angel. They can use the same powers as Devils kind of and Light Magic. I will also be the counter to most Devils.'
[Becoming a Fallen Angel? I can see the merit in this as Fallen Angels are superior to baseline humanity many times over. Especially the Cadre who are all Ultimate Class level beings. Azazel is even more so and by becoming a Fallen Angel most of your human weaknesses will be fixed without adding any more.
Light Magic can also be very strong to match my Liquid Darkness. You know, if you find a Fallen Angel that is trying to hurt you, if you kill it and feed it to your Sacred Gear, I should be able to give you its powers?]
'Where will we find one though?'
[Good question. I don't know.]
That was as useless as the scratch tickets so he didn't pay attention at the moment. Instead, he turned off the TV to go to his room to train with the Boost more to study Japanese and Math.
While that would be a bit boring, if he wanted to use magic or make his own, studying would make it worth it. However, just as he was going to do that he heard the doorbell ring.
He was going to get up to answer it, but his Mother called out to him.
"I got it."
He sat back down and waited as she went to the front door. When she opened it, outside the door was Aya looking down.
"Is Jack ok?"
Esmeralda smiled and nodded.
"He is, he is already home thanks to you. Come inside."
Aya nodded and was going to take off her shoes, but Esmeralda didn't care.
"You don't have to do that, this is an American home. Just kick off the snow."
Aya did just that before she walked inside with her. Since Jack was on the couch, it was obvious he was ok. He smiled at her.
"Thanks for saving my life, it was my fault."
Aya shook her head quite sad.
"I chased you in the snow, it is my fault too."
Esmeralda shook her head.
"You are kids, kids run. He just slipped, don't blame yourselves especially you Aya. You did nothing wrong."
Jack agreed as in a way it was a good thing he slipped. Not only did he remember his past life memories, he even unlocked his Sacred Gear. That was a really good thing as he was practically set for greatness.
Once Aya saw that he was fine, Esmeralda left to leave them alone. Aya sat on the couch next to him.
"Are you ok? I saw blood come from your head."
He nodded as he pointed at the small scar on his head.
"I am fine, the hospital cleared me. Instead of worrying, want to play some video games?"
"Ok."
Despite awakening his past life memories, he was still an eight-year-old kid. He and Aya brought out his game console and hooked it up to the TV in the living room. They simply played some of the video games he had for a few hours.
That let her see that he was fine, and video games were always fun. When the time came for her to go home, she simply walked home since they lived a few houses from each other.
"Bye Jack'O."
He waved her goodbye from the door.
"See you tomorrow."
As she walked away, he noticed how she was walking slowly. After seeing him hit his head after slipping she didn't want to slip either. He watched as she slowly walked home until she reached her house 5 houses down.
When she reached the door she waved one last time before going inside. When she was safely home, he closed the door before putting up his video games. Once they were safely in the closet, he returned to his room before closing locking the door.
He sat down at his desk before pulling out a journal. He got his pens ready and he got out his Japanese and Math Text Books. He held his left hand out before bringing out the Boosted Gear.
[Boost.]
Without the Balance Breaker or further training, he was limited to a Boost every 20 seconds. Of course, a minute later he was up to three Boosts meaning his thought speed was back to 8 times faster.
Not just that his Mana was overflowing through his body. Before he could study, he closed his eyes as he focused on bringing his Mana under control. Eight times the Mana of a near Ultimate Class Devil was a lot, but Apophis helped him out.
When he got it under control, he was surrounded by a pitch-black and crimson aura.
[Well done, kid. You managed to tame the overflow rather quickly. Most would have struggled.]
'Thanks, but, should I go for four?'
[No, I don't recommend it. 16 times the Mana of an Ultimate Class would be a lot for a human to control. That would bring too much attention.]
'Got it.'
Instead, he focused on keeping his Mana tame to keep the effect of the three Boosts as long as possible. With his thought speed accelerated he began to use his notebook and textbooks to begin to speed up his learning speed of Japanese.
It would still take him a while to get it down, but by relying on the Thought Acceleration of the Boost he could quickly become the smartest in his class. Plus, when he got a little older, he could invest in stocks that would succeed to make money.
As such, unlike yesterday when he did this, he managed to continue studying at this super speed for 15 minutes. When the Boosts wore out his Mana dropped, but a bit larger than before.
Not only that, but all the information he learned about Japanese settled down in his mind. However, it did hurt his head as he just absorbed a large amount of information rapidly.
'OWWW!'
[Get used to it. In the future once I fully adapt to this, it will get even harder.]
He held his head, but after calming down he was happy as it was working. In a week or two he would be able to start speaking some Japanese. In a month or year, he would be able to learn multiple languages and even begin to make his magic.
He was already loving the Abyssal Eclipse Gear and Apophis.
(Ok, version 2.0 with Apophis rather than Ddraig is coming along nicely.)