And this book is the supreme of the Talisman Dao, reportedly only possessed by the Divine Sect.
Ordinary people can study it for a lifetime and only learn a level or two of the basics of Rune Secret Spell Basics, but will never touch upon Secret Spell Script Study.
Even if they encounter it, they won't understand it.
Not even Jiang Feng initially.
As the requirements for cultivation techniques included in the panel became increasingly stringent, Jiang Feng felt that even if he acquired Secret Spell Script Study, without specialized study, it would be difficult to include it in the panel and grasp the essential techniques of He Ku's Profound-Grade Talisman.
Thus, when Jiang Feng now inscribes a Profound-Grade Talisman, it's akin to when he was atop Black Iron Mountain, having no corresponding text seal, relying on sheer passion and time investment to be able to complete talisman inscription.
He wasn't sure if success was possible, but wanted to try.
