Dan Lei, Tanjiro, and Giyu Tomioka had a smooth time watching the sunrise.
Tanjiro and Giyu listened to Dan Lei's stories about the outside world the whole time. Dan Lei had simply dressed up the Magecraft world of the Type-Moon universe and told it to them as a story.
Since almost all of it was true, Tanjiro's nose couldn't detect the scent of a lie on Dan Lei. Giyu even said that if he ever had the chance to retire, he would definitely travel abroad.
In the end, the deer Dan Lei had caught to draw a Heroic Spirit Summoning Circle with its blood didn't go to waste. Dan Lei had Kojiro Sasaki carry it to the mountaintop, where it became breakfast for the three of them.
Under the light of the rising sun, Giyu finally let down his guard around Dan Lei, who was bathing in the sunlight. Before leaving, Giyu somehow produced a piece of bamboo, fashioned it into a muzzle, and gave it to Tanjiro to keep Nezuko's mouth blocked, in case she suddenly lunged at someone and bit them.
Of course, bamboo wasn't strong enough to stop Nezuko if she really wanted to bite someone; she could break it with a single bite. Put simply, it was a measure that could deter the honest but not the dishonest. It was more for show than anything else.
After giving them the gift, Giyu took his leave. As a Hashira, he was quite busy, and he needed to write a report about his encounter with Dan Lei to inform his teacher and the master of the Demon Slayer Corps.
After parting ways with Giyu, Dan Lei and Kojiro Sasaki followed Tanjiro toward Sagiri Mountain.
Since this was the Taisho era, Dan Lei knew next to nothing about the land beneath his feet. He had only a vague grasp of a few place names.
As for how to get from the mountain where Tanjiro lived to Sagiri Mountain, Dan Lei said he couldn't make heads or tails of maps from this era, which looked like scribbles. Kojiro Sasaki was better at finding the way than he was.
So Tanjiro led the way the entire journey.
Just as Dan Lei had predicted, there were few things in this land that could cultivate using Ley Lines, but demons could absorb Ley Line magic naturally.
After observing for several days, Dan Lei confirmed that Nezuko could slowly absorb magic from the Ley Lines to replenish herself even when she wasn't asleep and was simply standing there.
Sleeping made her absorb Ley Line magic faster.
That was why she, having almost no energy expenditure from physical activity, could balance the energy deficit in her body during the early stages of becoming a demon and suppress her urge to feed.
After all, demons were said to love eating humans because human flesh contained more magic than that of rare creatures such as phantasmal beasts and magical beasts.
It was common knowledge that human blood was the easiest high-quality magical medium to obtain. Countless cult rituals explicitly stated that the ritual site should preferably be drawn in human blood.
The human instinct to eat was etched into DNA, so when a demon's body lacked energy, it naturally wanted to feed. Human flesh and blood, which contained magic, made the best food.
As for why demons found ordinary food disgusting after turning, it was probably like how people accustomed to rich, heavily seasoned food found plain food exceptionally bland and unappetizing.
Once ordinary food was processed, even ingredients that originally contained magic would have it destroyed by high heat. Without magical seasoning, eating it would naturally be like chewing wax to a demon.
Demons who replenished their magic by feeding for a long time would naturally lose their ability to absorb Ley Line magic and sustain themselves, since it had gone almost entirely unused. That was why Dan Lei thought the Ley Line energy in this place was unusually abundant.
However, all of these conclusions were based on Dan Lei's observations of just one demon, Nezuko. Without control experiments, their accuracy remained uncertain.
Of course, in his spare time, Dan Lei also compared notes with Kojiro Sasaki through telepathy, estimating what rank a Hashira like Giyu Tomioka would have among Heroic Spirits.
Well, it was probably better not to compare Giyu's combat strength to that of a Heroic Spirit. According to Kojiro Sasaki, if Giyu's attributes were rated like a Heroic Spirit's, his Luck was unknown, his Strength and Agility might be D, and the rest would probably be a sea of Es.
That level of combat power wasn't weak among magi, but among Heroic Spirits, he could probably only fight one of Hundred Personas' many clones when she split into the maximum number.
Of course, that assumed Hundred Personas' clone didn't use poison and had to fight him head-on.
From that perspective, the Lower Rank demons, whose combat strength was roughly equal to or even slightly below that of an ordinary Hashira, should be around that level too.
You might ask what kind of level Dan Lei's current Heroic Spirit attributes were at.
Dan Lei would tell you that his Strength and Agility were both around E+ (using Reinforcement Magecraft could make both attributes skyrocket); with the Abundance Destiny's blessing, his Endurance could probably reach C; in the Demon Slayer: Kimetsu no Yaiba world, his Mana had to be at least B; and as for Luck, he'd crossed over into another world, so it had to be A.
Still, despite Dan Lei's high attributes, if it came to a real fight, he might not be able to beat Giyu Tomioka if Giyu got close. The gap was in skill. Dan Lei had plenty of magic, but knew only a few spells specifically meant for combat, and his martial arts were very ordinary. In a fight, he could only bully weak opponents.
But as support and a healer, Dan Lei was absolutely professional. He hadn't forgotten the medical knowledge Dan Zhu had taught him, the Abundance Destiny was excellent for healing people, and he could also make puppets to assist in battle.
But in the end, what made demons powerful was their Blood Demon Art. Those abilities often defied reason, and even a Hashira could be caught off guard by a particularly troublesome one.
That gave demons an advantage over Dead Apostles. At low levels, a Dead Apostle might or might not be stronger than a zombie, depending on the circumstances. They wouldn't get a natural spell until they became a high-level Dead Apostle.
But it seemed that demons could awaken their Blood Demon Art naturally just by eating a few people.
Considering that Nezuko had awakened her Blood Demon Art without eating anyone, Dan Lei suspected, as he analyzed the phenomenon, that it might be a kind of blessing from the Ley Lines.
The fact that demons, who committed evil, were a species blessed by the Ley Lines was a hellishly ironic joke. So Dan Lei simply made a note of it and planned to find a way to verify it later.
After several days and nights of traveling at full speed, Dan Lei and the others finally reached the foot of Sagiri Mountain, where Dan Lei found his first subject for a control experiment.
It was the same temple from the anime. But this time, before Tanjiro even got close, Dan Lei used Magecraft to hear the disgusting sound of chewing from inside.
Since no one inside was still alive, Dan Lei didn't stop Tanjiro from approaching and opening the temple doors. He wanted Tanjiro to see a demon eating a person with his own eyes and understand how terrifying these monsters were.
Seeing the hellish scene again, Tanjiro was stunned, just as before.
But when the demon lunged at him, Dan Lei intervened.
He used Magecraft Threads again. They were the foundation of puppet control, and the spell he was most proficient with. Ordinary demons that couldn't even use Blood Demon Art weren't strong enough to break free of the Magecraft Threads.
So the demon was fixed in midair, frozen in the act of lunging.
Then Dan Lei pushed Tanjiro aside from the doorway and looked at the monster inside with a smile.
"All right, the heinous experimental subject has been captured. Now for the fun part: the experiments.
"Tanjiro, go dig a few holes behind the temple and bury these bodies. My experiment is going to get pretty bloody, so you'd better not watch."
All that could be said was that the original Fate setting—that Heroic Spirits could easily crush magi—seemed like wishful thinking from this perspective.
Leaving aside beings like True Ancestors, there had to be several magi whose combat power rivaled that of Heroic Spirits.
And in the UBW route, Medea had been beaten senseless by Rin in close combat.
Before you continue