The change stems from his Spiritual energy. Every time the natural energy flows in and out of his body, they influence his spiritual energy and enhances his constitution a little.
It was minuscule when it comes to his constitution but it had a tremendous impact on his spiritual energy. It may also be the reason for his abnormal 'Haki Reserve'.
The reason why he was able to sense the natural energy now, should be because of meditation. He had been meditating ever since he began to train in Haki.
Of course, he can't absorb natural energy and generate Senjutsu chakra since he has no idea how to do it.
But, the surprise brought by Natural energy is enough for him to be happy for days! Because his haki points raise by 0.1 every day when he meditates by absorbing Natural energy.
--
There was a huge change in his status panel after he mastered his Haoshoku Haki and completed the task.
[~ Task: Completely Master Haoshoku no Haki
Status: Completed
Reward: 5.0 Constitution+ 5.0 Devil Fruit Potential+ 5.0 Haki Points+ 5.0 Free attribute points ~]
The reward completely changed his attributes and elevated his combat strength to another level. A few months back his attributes were like this,
->Haki: 15.3
->Constitution: 41.2
->Devil Fruit Potential: 36.4
Every week his constitution attribute increased by 0.2 points while his Devil Fruit potential attribute increased by 0.1. So, after four months, they were raised by '3.2' and '1.6' respectively.
Combined with the reward, his constitution attribute grew from 41.2 to 49.4, just a little short of reaching '50' points while his Devil fruit attribute increased from '36.4' to '43.0'.
As for his Haki, they rose by 0.5 every week in these four months due to his heavy training. They increased from 15.3 to 28.5, adding the reward.
Blaize current status is as follows,
[~ Name: Blaize Hunt
Occupation: Marine
Constitution: 49.4
Devil Fruit Potential: 43.0
Haki: 28.5
Free attribute point: 7.0 ~]
The effect brought by the natural energy is exceptional and a huge boost to him. It's just Blaize doesn't know for how many days this perk will work, as he knew this kind of thing won't be permanent.
After some time, the effect natural energy had on his Haki will surely diminish. He needs to make complete use of it till it lasts.
Suddenly, a notification sound buzzed in his mind startling him completely. Blaize checked and was surprised to see a new task.
'The system issued a new task after a long time!'
[~ Task: Save Donquixote Rosinante and Kill Vergo.
Time: None.
Reward: 1.0 constitution+ 1.0 Devil Fruit Potential ~]
Viewing the system task, Blaize was lost in thought and recalled everything he knows about Rosinante and Law.
With his current strength, it won't be a problem for him to save Rosinante and kill Vergo. Hell, he's not even afraid of Doflamingo. But, it's a different story if had to face all the members of Donquixote pirates.
He can only complete the mission covertly but before that, he has other things to worry about. Aside from the fact the event will occur at 1511, he doesn't know the exact month and date.
Furthermore, he just can't simply leave the East Blue and visit the North blue when he's on duty. If he does that, then Sengoku may get angry this time, for real.
He needs a reason to visit the North blue. 'Since System released the task, there may be a reason let's wait!'
Blaize doesn't know how he would do in a real fight. After all, he hadn't fought any Haki users after learning Haki. His body is itching for a fight! So, just the thought of facing Donquixote pirates excited him.
--
Another two months passed by,
In these two months, the biggest improvement came from his spiritual energy as his haki points rose gradually; they increased from 28.5 to 34.5.
His constitution attribute stopped at 49.8, showing no signs of growth during the last two weeks. After pondering for days, Blaize decided to use the free attribute points and raise them to '50'.
'Boom!'
As soon as he did that, his physique had a huge and visible change. His hair grew longer while his eyes had a golden tinge around them.
He grew taller, standing around 6.7 feet in height. His shoulders widened a little, muscles enlarged with perfect proportions but there's no change in his lean frame.
His build held explosive strength while the feeling of unprecedented power coursed through his body. Especially his vitality, his entire being brimmed with energy and life force.
The rise in his physical strength enhanced his devil fruit potential and spiritual energy. Blaize thought in his head, 'How strong am I right now?'
Just as he was relishing the moment of power, Regis entered the cabin with a low knock on the door. But, he stood rooted on the spot noticing Blaize's change.
'How could a person change drastically in a single night?' Regis was sure, Blaize looked normal last night.
"Blaize-san, what happened?"
"Nothing, it was caused by a sudden increase in strength. Tell me..." Blaize asked.
"Yes," Snapping out of his thoughts and remembering his purpose, he quickly handed the Den Den Mushi to Blaize and said,
"Admiral Sengoku called, he wanted to have a word with you. Since you were busy in training, I didn't interrupt!"
Taking the Den Den Mushi, he dialed Sengoku's number. 'Purupuru...purupuru...purupuru...'
'Kacha!'
"Sengoku-san, Blaize here!"
"Blaize brat! How's East Blue, is it to your liking?" Sengoku spoke in a relaxed tone.
"I am bored as hell! I would be grateful if you send me to the New World, Sengoku-san." Blaize replied.
"Sending you to New World is the same as instigating a war. Sigh! It's too early for you to enter the New World and don't forget you are still under discipline."
"Aye. Aye. So, why did you contact me, Sengoku-san?" Blaize asked. He has an idea why the latter called him.
"Is anyone near you?"
Blaize looked at Regis and the latter left the room without any noise understanding the cue. Blaize then replied. "No, you can talk freely."
"I want you to do something." Sengoku then explained the deal regarding the Ope Ope no mi. "I have intel that Donquixote pirates will be there. I don't know how the trade got leaked.
The truth is, I don't want to share about this mission if not for my bad premonition."
Hearing this, Blaize's lips twitched. "Am I that unreliable?"
"Yes."
"So, what do you want me to do?"
"Nothing! I want you to monitor the Island in secret and wait for my orders. Make note, this an unofficial request personally from me.
If someone finds your whereabouts, there's a chance you may be directly dismissed from the Marines."
"Do I have to partake in such a risky mission?"
"You don't want to?" Sengoku asked back, knowing full well about Blaize's personality.
In fact, Blaize didn't want to do this for just two attribute points when he can gain them by simply training in one place.
And, the real troublemaker is Rosinante, godson of Sengoku. After thinking for a moment, Blaize decided to do it. Not for attribute points, but to save Rosinante.
He wanted to see how the future will develop, once he changes them. 'It's going to be entertaining, to mess with Dolfamingo!'
"I will do it!" Blaize replied while Sengoku updated him further about the details.
"The trade will happen two weeks from today! Reach the location a week before and monitor the situation, covertly!"
"Ok!"