In the past, Luo Zhen had believed that Ashiya Douman had survived for a thousand years by using forbidden spells, living all the way to the present.
The forbidden arts referred to here were not spells such as the Taizan Fukun no Matsuri, which had been classified as forbidden by Onmyo law, but true forbidden arts—spells identified as heretical from ancient times to the present, evil techniques that struck terror into people's hearts.
As mentioned before, if he disregarded human morality, took out all the forbidden formulas accumulated in his mind, and used them without restraint, Luo Zhen's strength could at least multiply several times over.
That was because, although forbidden arts were evil, they were undeniably extremely powerful. By paying a tremendous price, one could obtain corresponding power. Even if people despised them, considering them shortcuts, evil, deviations from the proper path, and things destined for a bad end, that still could not change the fact that once they were carried out, orthodox techniques found them extremely difficult to withstand.
Take the Soma Family's spirit-summoning ritual, for example. Yakushimaru and Kumomaru had paid with their own lives and disregarded the citizens' safety to trigger two consecutive terrifying Spiritual Disaster attacks and stir the Spirit Vein into activity. That had merely been one part of the ritual. It was already a terrifying grand forbidden spell, yet compared to true forbidden arts, it could be considered quite mild.
Leaving everything else aside, rituals that sacrificed hundreds of lives, using those hundreds of people as offerings, could produce tremendously powerful effects and strength once successfully performed. Compared to such evil forbidden arts, was it not mild to pay with only one person's life to trigger a Spiritual Disaster and cause a terrorist attack?
Yet many similarly evil forbidden arts had appeared throughout