The dark blue crystal in the hand is not a regular diamond, but a polyhedron, and the overall shape is diamond-shaped.

Du Fei remembered that when he used Amaterasu to burn through the torso of the corrupted giant tree before, he seemed to vaguely see a touch of crystal blue. However, at that time, the burden on the right eye was too heavy, which also affected the left eye, and the durability of the left eye was almost half consumed, so the vision was blurry.

At that time, it was important to escape, there were black flames all around, and I had to use a metal wall to block the black flames, and I rushed out in a hurry, so I didn't pay much attention to the touch of blue, but I didn't expect to be taken by the little demon king.

The crystals were a little cold in the hand, and they didn't feel any energy at all, and they were as calm as a piece of tinted glass, but the exchange system did pop up a prompt.

Du Fei estimated that this piece of dark blue crystal should be the core energy of the corrupted giant tree, and it was indeed difficult to cultivate an advanced evolution in a short period of time with the energy of the density of the energy crystal. Du Fei originally wanted to break a small part and keep it and store it as crystal energy. It's just that he can't do it with all his might, with Du Fei's current strength, even a diamond can be broken, but he can't break this piece of blue crystal.

If you understand it according to the knowledge of atoms, the distance between the atoms in this crystal is smaller than that of diamonds, but there is no such substance in nature, and even if it is synthesized by humans, it can only make carbon nitride, which is slightly harder than diamonds.

Du Fei could only think that this crystalline substance did not originally exist in nature at all, and perhaps it was formed by the condensation of photons.

Du Fei didn't dare to use too violent means to deal with this crystal, because according to the content of the exchange system, the material energy density that can reach high-grade crystal energy is at least a hundred times that of energy crystal. In other words, the energy contained in 1g of this dark blue crystal is at least hundreds of millions of joules, and if it explodes, it will kill a small person.

Since you can't leave some for research, it's good to absorb it, and the advanced crystal energy exchange system is indeed very curious.

As a result, Du Fei stored the crystals as high-level crystal energy and activated the crystal energy system. Then the system pops up the interface of the advanced crystal energy system.

At the top of the interface is a row of diamond-shaped crystals, but these diamond-shaped crystals are transparent, except for the first and second halves of the front one, which are dyed dark blue. The number and unit of crystal energy are shown below: 1.6 crystals.

Then there is the explanation of crystal energy and crystal energy systems.

The exchange system is to use energy to achieve exchange, if it is only the transformation of the material structure, then the energy provided by the energy crystallization is sufficient. However, when the power and level of the exchange item is too high, it is necessary to provide energy cores, and energy crystals of normal energy density are not enough to support this. It is necessary to look for high-energy energy sources with higher energy density and more stability.

In layman's terms, it is impossible for human beings to use hundreds of millions of ordinary No. 7 batteries as energy for rocket launches.

Exchange items above BB in the exchange system need to use high-grade crystal energy to exchange in order to exert their full power. Of course, it can also be exchanged with ordinary energy points, but the skills and items obtained by exchange are semi-finished products, and only about 50% of the power of the complete product is achieved, and the other 50% of the power needs to be replaced with high-grade crystal energy to achieve it. And as the level of the exchanged item increases, the proportion of crystal energy required will also increase.

In other words, the exchange items above the BB level need to consume half of the high-grade crystal energy to redeem. The density ratio of ordinary energy to crystal energy is, 1 crystal = 100,000 energy points.

Du Fei checked the existing energy points, a total of 180,000 energy points, including 60,000 points left before the battle and 120,000 points collected in the previous defense battle. With the addition of 1.6 units of crystal energy, it can already be exchanged for a BB-level skill or item. And the advanced crystal energy system can break through the exchange level limit of the exchange system, which is what makes Du Fei the most happy about the crystal energy.

Now that the right eye is finished, there is no Amaterasu, so a high-power skill is missing.

Du Fei didn't want to exchange the Amaterasu Kaleidoscope anymore, because there were a few hot currents flowing in the right eye that had exploded now, and there was always a feeling in his heart that this scrapped right eye was very likely to give himself a big surprise.

Although the level 4 awakened person does not yet have the ability to regenerate limbs, he already has the ability to recover organs, and even if his heart is injured, as long as he is not completely smashed into mud, he can slowly recover. And Du Fei has several abilities in his right eye repairing, but the speed is very slow, and it is estimated that he will need to be blind for a few days.

Du Fei began to rummage through the BB-level redemption items, hoping to find a powerful skill or weapon from them.

I flipped through it, and I saw the slashing knife, although it looked very powerful, but Du Fei felt that what could be recognized at a glance was really annoying. Writing wheels are also often recognized, and they are often restrained. So Du Fei decided to DIY a weapon himself.

The "Wind Sword" has been used for so long, in fact, it is quite handy, but it is getting less and less powerful, and sometimes I am too lazy to take it out. Even though the hardness of the sword blade has been raised to the maximum, it is still a little weak.

Du Fei had a flash of inspiration and began to rummage through the exchange system.

The King's Treasure? Grass, so expensive.

Magma Fruit? No.

Smoking fruit? No.

Thunder Fruit? This is good, but you will be afraid of sea water when you eat it, and if you are framed by those ill-intentioned guys, it will easily become a cup.

But it didn't matter, and I didn't say I wanted to eat it myself.

Of course, it's not for others to eat, such a fierce thing for others to use, unless the brain is caught by the door.

By the way, Du Fei is preparing to give the "Wind Sword" a "Thunder Fruit".

Can weapons eat Devil Fruits? Anyway, it's okay in the One Piece world, the origin of the Devil Fruit. What's that technology called? Oh, and by the way, the new technology of the Great Passage allows items to "eat" Devil Fruits.

As for the question of whether the Thunder Fruit is not an animal fruit, it is just the right time to be a woman, and it should be possible to beast the Devil Fruit.

Du Fei flipped through the exchange system, not only did he have the "New Technology of the Great Channel", but also the "Super New Technology of the Great Channel" that allowed items to eat the natural Devil Fruits, and it was not very expensive, 30,000 energy points, just enough to afford.

Du Fei didn't hesitate any longer, exchanged for the [Thunder Fruit], and fed the fruit to the "Wind Sword" with the "Super New Technology of the Great Channel".

[Thunder Fruit] is one of the strongest Devil Fruits in One Piece, the "Natural Fruit", and is known as one of the invincible fruits. Those who eat the Thunder Fruit can control lightning, create lightning, and turn their bodies into lightning.

The purple light flashed, and the "Wind Sword" in Du Fei's hand burst out with brilliant blue thunder, which was very dazzling. As soon as his mind moved, the "Wind Sword" turned into a thunderbolt the thickness of a bamboo trunk, which was intertwined and intertwined on his arm, like a living electric eel.