After Ye Feng became familiar with it, the efficiency of spirit refining became faster and faster.

Basically, when it comes to the back, it only takes 3 seconds to refine the spiritual sea of a fourth-order mutant spider, only 6 seconds for the fifth-order one, and 10 seconds for the sixth-order one.

Of course, in the future, Ye Feng will basically only select sixth-order mutant creatures for spirit refining, and the reason why this is so is of course because of the harvest.

For example, if refining the spiritual sea of a fourth-order mutant creature and obtaining a spiritual origin is 1, then refining a fifth-order mutant spider is 10, and refining a sixth-order mutant spider is 100.

And a sixth-order mutant spider provided Ye Feng with a spiritual origin that was 100 times that of a fourth-order mutant spider, but the time to refine them was only a little more than three times the difference.

If you want to maximize efficiency, Ye Feng naturally knows how to choose.

But even if Ye Feng was only refining a sixth-order mutant spider, these 500 sixth-order mutant spiders would take a full 83 minutes.

It took so much time, and the harvest was great.

When the last mutant spider was also refined, the size of the golden crow swelled by nearly one-third compared to before.

Of course, this is only the first step, when the Golden Crow returns to the Spirit Sea, Ye Feng also needs to go through the Golden Crow Refining Method, and integrate the spiritual origin in the Golden Crow's body into his spiritual sea, so that he can be regarded as completing a round of real refining.

This is equivalent to using the golden crow to transfer once, so what he obtains, the spiritual origin, can fit with himself.

Ye Feng could clearly feel that the sea of spirit was constantly expanding, and his spiritual power had also begun to improve rapidly.

After 5 minutes, this round of ascension stopped, Ye Feng felt it carefully, and after just one round, his spiritual strength actually increased by 5%.

"It's really worthy of the Spiritual Power Secret Technique that even Heavenly Court has to pay attention to, and the effect of this improvement is immediate! At this rate, in a maximum of one day, my mental strength will increase by 100%. ”

Ye Feng couldn't wait to start searching for the place where the mutated creatures gathered.

Of course, before that, he would open the tactical computer, check the various squads, and send back a battle report every half hour.

After confirming that nothing was wrong, Ye Feng immediately set his sights on the valley 5 kilometers away, where there was also a huge mutant spider nest.

And the number of sixth-order mutant spiders is even larger, about 700 of them.

As soon as Ye Feng took a step, with a wave of spatial turmoil, his figure appeared above the valley.

Just as Ye Feng wanted to make a move, his gaze fell on a group of mutated wild wolves wandering around the edge of the valley.

This group of mutant wolves obviously wanted to fight this valley, to be precise, the prey on the spider webs in the valley.

Of course, Ye Feng didn't have time to care about what these mutant wolves wanted to do, his eyes fell on the three sixth-order mutant wolves led by him.

"Speaking of which, I haven't tried to refine the spirit of these sixth-order mutant animals!" Ye Feng whispered to himself, took another step, and appeared in front of the mutant wolves.

These mutant wolves' intuition of danger is far superior to that of those mutant animals, and the next moment they saw Ye Feng, they did not attack, but instead picked up their tails and began to run away.

It's just that in the face of Ye Feng, how could they escape, and in the blink of an eye, all the mutated wolves fell into the illusion.

Immediately after that, the golden crow reappeared and crashed into the spiritual sea of a sixth-order mutant wolf.

In an instant, Ye Feng sensed that the spiritual sea of these mutant animals was much stronger than that of mutant insects, at least twice as much.

But for Ye Feng, it was just like that, as the spiritual flame rose from the golden crow's body, the entire spiritual sea began to collapse rapidly.

This time, it took Ye Feng about 20 seconds to refine the spiritual origin in the spiritual sea of this mutant wild wolf and integrate it into the Golden Crow.

"Damn, it's a loss!" Ye Feng couldn't help but mutter.

Of course, the reason why he said this was not that he had obtained too little spiritual origin from the mutant wolf, on the contrary, it was more than he expected, and it was actually 5 times that of the mutant spider.

It takes 2 times as much time to get 5 times the income, in other words, refining these mutant animals is 2.5 times more than refining the mutant insects.

The reason why he said that he lost money was naturally because he had just wasted more than an hour on those mutant spiders.

But now that I've found out, it's not too late.

He quickly refined the three sixth-order mutant wild wolves, and then directly let the golden crow release the spiritual fire and kill all the remaining mutant wild wolves.

"Next, it's time to find the mutated animals."

Ye Feng's spiritual power began to sweep through this area on a large scale.

With his current strength of spiritual power, the farthest probing distance could already reach hundreds of kilometers, and as he closed his eyes to investigate, soon one by one mutated animals at the peak of the sixth order were searched out by his spiritual power.

Of course, Ye Feng didn't leave immediately, but easily dealt with the more than 700 sixth-order mutant spiders in this valley, and then left.

In the blink of an eye, half an hour has passed.

Although Ye Feng had only refined 90 mutant animals in this half hour, his spiritual power had skyrocketed by another 5%, and the total increase had reached 10%.

This kind of ascension speed is naturally extremely fast, but the smile on Ye Feng's face disappeared.

"I really didn't expect to reach the limit so quickly." Ye Feng muttered softly to himself.

Of course, the limit he was talking about was not that the spiritual sea could not continue to expand, but that he could accommodate it in a short period of time.

Although what Ye Feng absorbed back was all spiritual origin, and it had undergone the transformation of the Golden Crow, it was a foreign thing after all, and it needed to complete the last step of assimilation before it could completely become his own thing.

In fact, this assimilation has been going on all along, and the spiritual source absorbed back over time will naturally become his.

But the problem was that Ye Feng's efficiency in absorbing the spiritual origin was too high, and in less than two hours, his spiritual power had skyrocketed by 10%, which caused the speed of assimilation to not keep up.

And 10% is an upper limit, if Ye Feng continues to increase his mental power crazily, then there may be problems.

So all he has to do now is wait.

Ye Feng silently felt it, it only took half a day, then his spiritual sea would be able to completely assimilate these newly absorbed spiritual origins.