It was already three days later when they returned from Shi Jingcheng's residence. Those three days had been a wondrous experience for both Jiang Hai and Xuan Ziwen.
They had personally witnessed a Level 9 Soul Engineer achieve breakthroughs as both a Soul Engineer and a Soul Master, and their journey through the arrays had also brought tremendous benefits to their future cultivation and Soul Tool research.
Inside Civilization Research Institute No. 49, Yu Lang and the others had already begun researching and refining the core arrays of the Lifebound Soul Tool.
The more they worked with these arrays, the more amazed Yu Lang and the others became at Jiang Hai's brilliance.
Although these arrays combined barely reached the standard of a Level 8 Soul Tool's core array, and still had many flaws, even they were certain they could never create such remarkable arrays themselves.
Only someone whose understanding of the human body had reached the utmost depths could create arrays like these.
The more they researched, the more they wondered whether Jiang Hai had dissected countless Soul Masters to understand the human body's structure to such an extent.
Seeing Xuan Ziwen and Jiang Hai return, Yu Lang immediately came forward to report their research progress over the past few days.
Research into the Lifebound Soul Tool had only just gotten on track, but the reply from Illustrious Virtue Hall had already arrived, and all the resources they requested had been delivered.
Yu Lang took out a sandalwood box and handed it to Jiang Hai. "Director, this is the Soul Bone with the Four Symbols bloodline you requested. Illustrious Virtue Hall really bled themselves dry this time. There's only one Soul Bone with the Four Symbols Divine Beast Bloodline, but it's an exceptionally precious Head Soul Bone. By our estimate,