According to the Introduction to the Five Talisman Scripture, the first condition for drawing a Heavenly Immortal level talisman is that the person must have reached the realm of the Nascent Soul.
Well, as for this condition, Shu Guan has no problem.
Although his Nascent Soul stage is rather insubstantial—his spiritual power's intensity only being comparable to a cultivator in the middle to late Fetal Movement stage—he truly does possess a Nascent Soul.
The second condition is to have profound accomplishments in the art of creating talismans.
One must be capable of comprehending the mystic Daoist principles contained within an Immortal Talisman and possess the ability to draw those exceedingly complex rune patterns with utmost precision.
Actually, that's two conditions.
However, these two conditions did not pose any problem for Shu Guan either.
