The person who achieved Core Formation is Qin Yanyang.
Qin Yanyang originally possessed extremely high cultivation talent. She had been cultivating in White Jade City for years, and with ample cultivation resources and dual cultivation with Yang Fei, her progress was nearly on par with Yang Fei.
Especially after the last encounter with Yang Fei where they received the blood essence feedback from the Ten Directions Heavenly Furnace, her realm was elevated to the Peak of Late-stage Foundation Establishment.
Compared to Yang Fei's realm, she was only slightly inferior.
As for Divine Sense strength, because Yang Fei once took her and Tong Yunshu into a special state of traveling in the Divine Void, her Primordial Spirit strength had reached the level where she could impact Core Formation.
