Rino cut to the chase. With his shadow army busy with the farm and shelter construction, he decided to ask his dark magic teacher to start the first class.

"I want to know the basics of dark magic," he told Kragami, who settled on the little stool because Rino was sitting on the mattress. 

There really wasn't much in the hut, and this was the only abode in the farm they were in. He was slightly curious how Rino managed the rest of his undead army. Did he un-summon them when it was daytime?

Instead, he kept those questions to himself for now.

"What do you understand about dark magic?" Kragami asked. It was better to check Rino's progress than to assume this lich knew nothing.

Rino only listed the dark magic spells he knew and explained the theory of mana he recently discovered thanks to Noir's hint, although he did not reveal who he learned his magic from.

Impressed with his profound understanding of mana and its origins that Kragami did not know, the necromancer asked if Rino researched or studied any other types of magic.

Hearing the ex court magician list the things he studied in his previous life, Kragami became more puzzled. Why in the world would a lich study light magic and holy magic? Also, his student appeared to be closer to an elemental magician and an alchemist more than a summoner.

His character was a complete mismatch with what he turned out to be.

"C-can I stop you here and ask you one question?"

Rino paused. He was still reciting the number of magic languages he knew when the old man stopped him.

"What is it?"

Kragami thought of the best way to phrase his question without offending the overwhelmingly talented magician before him.

"Why did you study everything else but dark magic when you're going to become a lich?"

Rino paused. How should he explain to his teacher that becoming a lich wasn't his choice? In fact, getting reborn into a new world wasn't his decision either.

"I was cursed," Rino explained in one line. "None of this is my choice. I just want to research peacefully, but something went wrong, and now I have to build a kingdom with the blessing of gods and the curse of immortality. Does that answer your question?"

While it made little sense, Kragami figured that this was the most his student was willing to share. He nodded and listened to Rino list off the rest of what he knew about magic.

If this was still the magician tower in his previous world, Rino would receive a standing ovation just for stating his knowledge. People would worship his existence, and every new young witch or wizard would ask for a handshake from him like some kind of over popularised idol. Not even the king would receive such a heartwarming welcome with adoring attention.

However, his new magic teacher remained unmoved by his impressive ocean of knowledge. He only concluded one thing that made Rino's heart and self-confidence plummet.

"So you don't really know anything about dark magic, not even the basics?"

Unable to deny or refute the statement, Rino looked away. He was a court magician and not a cult leader in his previous life. Besides, there were not many books about dark magic in the royal library.

Seeing Rino's silence, Kragami took it as a sign to start from the beginning. Given Rino's vast knowledge about magic in general, his student should have no problems grasping the fundamentals.

"Let's start from the basic theory," the necromancer suggested.

Rino did not protest and sat upright, listening intently.

After understanding the source of dark magic that was simple enough, Kragami broke down dark magic into three sub-branches.

"The most basic uses of dark magic can be classified into three types. Unlike elemental mages who can only use spells according to the elements their mana is compatible with, dark magic is universal, much like light magic."

Rino understood this quickly and realised that unlike light magic and elemental magic produced within a magician, dark magic was moulded by the magician but stored and created from an external source.

"Dark magic is not a source from within, it is a source from outside, and the magician is merely a translator of that energy into different uses. Hence, there are three ways to convert the dark and negative energy."

The first was an emission that Rino was rather familiar with. His shadow tendrils were the basic form of dark magic emission. However, Rino soon realised why he found it difficult to maintain control of the tendrils and why they snapped after a certain distance.

"Emission is dependent on the spellcaster's field of control. Unlike elemental mages who use the environment as their field of control, dark magicians often have a fixed field of control. The only way to extend this field of control is to lay an array linked to the spellcaster."

That would explain why Rino could never get his shadow tendrils to go further than a certain distance unless more shadow tendrils were present to extend the overall reach.

The next use of dark magic was also something Rino discovered from the skills given by his quest system. Kragami called them portals, but Rino preferred to refer to them as passing through realms.

"Knowing how to create portals, you can travel long distances in short amounts of time, slow down time, manipulate the field of gravity, store items in a separate space and many more. Portals are limitless, but the size and ability of any portal are directly proportional to your control of magic and available mana."

Rino had exceptional magic control and a very large pool of mana. That would explain his shadow sack ability and why he could chuck just about anything into it. Chucking things into the shadow realm and only opening it to retrieve the items when he wanted has a shorter portal summoning time than travelling through the shadow realm to teleport. The portal gates for teleportation remained open until the spellcaster emerged from the shadow realm to close it. 

Time flow within the shadow realm was slower than the material plane, and Rino learned that by keeping the portal closed and only opening when he needed it, he could do many interesting things.

The last category of dark magic manifestation was soul magic. This was slightly similar to how holy magic was a special ability even among light magic users. Only a few dark magicians could use this sub-branch of magic.

"Soul magic is the highest tier of dark magic that only the mentally strong may challenge. When a dark magician stares into the abyss, the abyss stares back at them. It isn't the same as summoning a demon or a mass sacrifice for plague curses. Those are tricks for elementary occults who think they are on the same level as dark magicians who know how to manipulate a soul."

Kragami knew that Rino had it in him to perform soul magic level spells from their fight earlier. Soul splitting was common for those who could summon the undead. Many would use this basic spell to create puppets and spare bodies as a form of insurance. This was nothing new to Rino.

However, when Kragami explained that life manipulation, curses and advanced summoning rituals were part of the soul magic category, he was interested.

"For now, you will practise some basic dark magic spells," Kragami told his eager student with a chuckle at Rino's obvious disappointment when he refused to elaborate what an advanced summoning ritual could do.

The lich grumbled when Kragami crammed over a hundred basic spells into his head and excused himself for the rest of the day. The necromancer simply wanted to have a look around, and Rino could not stop his teacher.

Instead, he summoned Erika over to be his study companion until the sun went down. Students shouldn't suffer alone. After all, sharing was caring.