Night.

The afterglow of summer has not yet dissipated, and after nightfall, the Crescent Academy still carries a little heat, and it will be at least another week before the autumn breath completely takes over the entire continent and lowers the temperature.

Reiner opened the window, and he saw downstairs, Fina was feeding the kitten, and the two were having a good time, Reiner smiled and didn't say anything.

He sat back in his chair and looked at the parchment on the table.

On top of this, there's a spell model.

Even if you look through any magic book on the entire continent, you won't find a spell model that is exactly the same as the one depicted on this parchment, and its complexity is far beyond that of ordinary low-level spells, enough to meet the standards of the Three Rings.

After studying several four-ring circles, Reiner discovered a wonderful thing.

It's called mid-level magic, and its spell model is just three-dimensional.

No matter how complex the low-level magic is, all the spell nodes and magic channels are also on the same plane, and they can be included with just two axes, even the three-ring magic that the spell nodes and magic channels will change.

When it comes to the spell of the four rings, there is an extra coordinate axis on the plane immediately, becoming a three-dimensional spell model, however, the spell nodes and magic channels of the four-ring spell are also fixed, as long as the geometric relationship in the three-dimensional space can be correctly understood, then the four-ring spell is actually even simpler than the three rings.

Being able to engrave the four-ring spell in the heart lake has the capital to advance to the middle level, but for the mages, how can the breakthrough from plane to three-dimensional be so simple, although it seems that there is only one more coordinate axis, but the calculation changes it brings are far from so simple.

With this realization, it was a relief for Reiner.

With his computing ability, it is not easy to deal with the four-ring spell, if the four-ring spell requires other aspects, then Reiner may still be a little worried, but he didn't expect that the four-ring spell actually tests the spatial calculation ability of the mages, which is what Reiner is best at.

However, before he could engrave the four-ring spell, he also needed to incorporate the three-ring spell in front of him into his heart lake.

It was a spell he had designed for his own situation, and it had extremely special properties, and although he didn't dare to say that there was no one to attack him, at least it had no analogues in the history of magic.

Reiner checked the parameters of the spell model again before closing his eyes.

It took about fifteen minutes for him to return to reality from the world of the Heart Lake, and when he opened his eyes again, Reiner knew that the three-ring spell had been engraved into his Heart Lake.

To be honest, he didn't want to use this spell at will, on the one hand, it was one of his means to save his life, and he couldn't show it easily, and on the other hand, this spell was so destructive that unless the enemy was a clear threat to him, Reiner would still have leeway.

After inscribed the three-ring spell, Reiner was actually enough for the three-ring mage, and as long as he was stable for a while, he could immediately attack the four rings.

In just half a year, he has been promoted from a mage apprentice to a mid-level mage, and I'm afraid that few people can believe it.

But Reiner's situation is extremely special, he has discovered major breakthroughs one after another, and the world feedback he has received is top-notch in terms of quantity and quality, and the magic power brought by these feedbacks is abundant, enough for Reiner to break through to the highest level, but rather, it took him half a year to advance to the fourth ring, which is too slow in the eyes of some high-level mages.

The improvement of magic strength does not simply rely on the improvement of world feedback, but more about the familiarity with magic, the control and use of magic, which requires a certain amount of time to accumulate, and it is not that the faster you advance, the better.

Feedback from the world can greatly speed up this process, but it can't make an apprentice move up to a higher rank overnight.

Excluding Reiner, in the history of modern magic, there is only Isaris. Lord Alberton's ascension was much faster than usual, it took him five years to advance from a Ring Mage to a High Mage, and the step from High Mage to Legendary Mage took another five years.

This speed of promotion is unique even in the entire history of magic, not to mention Alberton's time, many theories have been proposed, new sources of feedback from the world have not yet been found, and he, starting from movement and force, has forcibly opened up a whole new field.

But even if a legend like Alberton is promoted, his speed up to the middle tier is not as fast as Reiner's.

Even if you don't take into account the feedback that Reiner's research may get from the world in the future, his current accumulation is enough for Reiner to surpass the speed of Alberton's promotion, and at the current rate, at most, in three years, Reiner can try to cross the intermediate level and enter the threshold of a high-level mage.

And a large part of the reason why Reiner is so eager to improve his strength is that he decided to join Erasmus's magic expedition.

He made such a decision after some consideration.

First of all, Reiner himself is very curious about the half-plane, he has never been to any half-plane, naturally yearning for this unique environment, and wants to experience it on the spot, but most of the half-planes have certain dangers, even if they are marked as safe, they may encounter accidents, and now there are so many mid-level mages in a team, which is enough to minimize the possibility of accidents.

Secondly, Erasmus has unique and rich animal and plant resources, which will be helpful to Reiner's research, just like going to Norse before, Reiner is also ready to collect some special magical creatures to cultivate if he has the opportunity.

In the end, Reiner said to the Potsdam . Baptiste was also a little curious.

As he noted, Potsdam. Baptiste's father was the same person who wrote Where Are the Magical Creatures? Scarder. Baptiste.

Scudder. Baptiste spent his life trying to figure out the laws of species evolution, but he did not succeed, leaving only a posthumous work on the ecology of various half-planes, and it seems that his son Potsdam inherited his father's legacy and developed a new interpretation of species evolution.

It is a product of the times on the earth, and it is not a comprehensive evolutionary theory, because it emphasizes the role of subjective initiative, but this is a world of magic, philosophically speaking, magic is the product of idealism, although Reiner is currently in contact with this world, many materialist theories are still universal, but he does not dare to draw conclusions without authorization, and still needs to be carefully investigated.

For the rest of the year, there was nothing for Reiner to focus on, he could do some of his own things, and joining the magic expedition seemed like a good choice.

As for what the letter said, you can bring a student with you, and Reiner didn't intend to waste this opportunity, he already had a candidate in mind.