The 'Zhi' Formula in the 'Interpromotion and Interrestraint' of the Taixu Strategy was enough for Shen Lian to gain an insight to most of the spells in this universe and the profound theories of the spell formations. The Chunyang Daoist Palace's Heaven Span Formation was still ingenious but it could not hide from Shen Lian's Dharma eyes.
No matter how those two thought, they would have never ever guessed that Shen Lian came from a very extensive background. The ten sects of the Tianhua Continent still have a profound heritage but the Qing Xuan Daoist Sect did not shy far away from it. Throughout the entire Tianhua Continent, they would not have found the Dao formulas that would be on par with the Taixu Strategy.
Shen Lian, being the sect master of the Qing Xuan, he was one of the most distinguished figures in the world of cultivation in the Yuan Continent. If this formation could have stopped him, people would have laughed their heads off.