This exceptional rate of improvement beyond comprehension made them feel excited, yet at the same time, somewhat worried.
A too-rapid increase in strength isn't necessarily a good thing, especially such an inexplicable one.
Thus, they had just been discussing the reason behind it.
Xiao Zhan used a bit of his spiritual power to search for the reason, a lengthy process requiring examination of various factors, Artifact Spirit Space, Contractual Power, Spirit Manipulation Energy...
Fortunately, Xiao Zhan had plenty of time.
Time passed outside.
Soon, it was noon.
Ye Wudi, seeing no one at the dining table, asked in confusion, "Where have the lady and the son-in-law gone?"
Whether or not he acknowledged Xiao Zhan was one matter, but in front of the servants, it was necessary to give face to Xiao Zhan as the half-master of the house.
Thus, addressing him respectfully as son-in-law was a must.
"Reporting to the General, the lady and the son-in-law are cultivating in the training room."
"Alright, understood."
If they were in the training room, there was no need to wait. Cultivation knew neither time nor day, and it was uncertain when it would end.
Ye Wudi began to eat.
Meanwhile, Xiao Zhan continued to sense for the reason.
In this state, the passage of time in the outside world seemed very fast.
By evening, he hadn't stopped, continuing to cultivate until the next morning, when Xiao Zhan finally felt a surge of joy as he discovered the cause.
Just as he identified the cause, suddenly, his Artifact Spirit Space underwent a change.
The space, originally the size of a pellet, suddenly expanded significantly, and the Origin Energy within it became more abundant and purer!
With the expansion of the Artifact Spirit Space, it could absorb and filter more Spirit Manipulation Energy, causing the energy to merge in greater amounts and further enhancing the refinement of the Death Demon Scythe!
Xiao Zhan was overjoyed.
According to instructional descriptions, this was a sign of a breakthrough in his power.
First Grade Spirit Master!
He found it unbelievable; it had only been one day, yet he had already advanced, becoming a true Spirit Master!
His emotions surged indescribably!
He immediately ended his cultivation state, and the Death Demon Scythe transformed back into Ye Youlong before his eyes.
Ye Youlong's eyes also showed the same surprise as Xiao Zhan!
In this world, cultivation strength is distinctly divided, into a total of nine ranks, with First Grade being the weakest and Ninth Grade the strongest!
As most people dissolve their contracts, male Spirit Masters are called First Grade Spirit Masters, Second Grade Spirit Masters... up to Ninth Grade Spirit Masters.
While female Artifact Spirits are called First Grade Artifact Spirits, Second Grade Artifact Spirits... up to Ninth Grade Artifact Spirits.
Now, Xiao Zhan and Ye Youlong had simultaneously broken through to First Grade!
They were exceedingly delighted.
"According to the instructions, it generally takes half a year to break through to the First Grade realm with two S-grade contracts. With two SS-grade contracts, it takes about one and a half months. As for our type, SSS-grade, data is sparse, but it indicates it could take five to seven days to break through to First Grade!"
"Just the two of us, we broke through in a single day; counting rest, it amounts to two days, but this speed is also about two to three times faster than others of the same talent!"
"That's too extraordinary."
Ye Youlong, staring into Xiao Zhan's eyes, spoke with a mix of shock and concern.
This matter was a good thing, but it was also a bit too mysterious.
"Don't worry too much, I have just understood the reason," Xiao Zhan assured.
Then he explained, "After observing various energies within my body, I noticed that my bloodline power was being pulled when we cultivated. Normally, bloodline skills automatically strengthen with one's own increase in strength and don't require deliberate cultivation."
"But when we cultivated, it flowed along with us, so, I suspect that it must be my bloodline skills that accelerated our cultivation speed."
Hearing this, Ye Youlong became puzzled, "Your bloodline skill is Contract Expansion, not accelerating cultivation speed. How could that be related?"
Xiao Zhan shrugged, "I don't know, I can only detect this particular point. If you think it's not it, I can't think of any other reason."
In fact, Xiao Zhan's guess was correct.
His Bloodline Talent Skill, Contract Expansion, did not just merely expand; it also conferred him 'expansion amplification' in cultivation.
What does 'expansion amplification' mean? It simply doubles the effects of cultivation.
If Xiao Zhan's Bloodline Talent Skill, Contract Expansion, only simply increased the number of Artifact Spirits, then a problem would arise: he would find that his Artifact Spirit Space was just fixed to a certain size.
The total amount of Spirit Manipulation Energy absorbed would be just that much.
How would energy be divided among several Artifact Spirits in the same Artifact Spirit Space?
Each Artifact Spirit would only get a small amount, and the more Artifact Spirits there were, the less each would receive. Consequently, the feedback Xiao Zhan received from the Artifact Spirits would also be less.
This would in turn indirectly slow down Xiao Zhan's cultivation speed!
The effect of 'expansion amplification' essentially compensates for this problem.
After Xiao Zhan contracted the first Artifact Spirit, the 'expansion amplification' effect would emerge, displaying double the cultivation effects for him and the Artifact Spirit.
After contracting the second Artifact Spirit, the 'expansion amplification' effect still existed, but it would change at this point.
That is, the effect wouldn't increase further but would decrease from double to one and a half times the cultivation effect.
After contracting the third Artifact Spirit, the cultivation effect would become one and a third times more effective.
And so forth.
The cultivation effect amplification would gradually decrease with each additional Artifact Spirit, but this multiplier would always be between one and two!
It would never be less than one.
That is the real strength of expansion amplification!
But it also imposed a constraint, limiting Xiao Zhan's choices.
To enhance his strength quickly, he couldn't contract too many Artifact Spirits. To have more Artifact Spirits, his strength couldn't rise quickly.
But actually, Xiao Zhan was always in a no-lose situation; no matter how slow his cultivation speed was, it was still faster than others of the same talent!
At this moment, because Xiao Zhan hadn't contracted a second Artifact Spirit, he wasn't aware of this effect, but he had observed and perceived some of the issues through his observations.
However, to fully understand it, he would only realize it the day he contracted a second Artifact Spirit.
But for now, they could at least confirm that there were no hidden dangers in this boost in speed.
"Let's leave it at that for now. Whether or not there are hidden dangers, we can only keep cultivating," Ye Youlong said.
She didn't know the real reason and could only trust what Xiao Zhan said.
"Are you hungry? Shall we go out to eat?"
"It's been a day, definitely hungry," Xiao Zhan said, rubbing his stomach.