Even if Niu Tongtian and the other twelve performed the Hun Tian Sword together, each studying one of its thirteen styles, the Green Demon King would still have to personally teach them the underlying principles.
That was because the Hun Tian Sword was so profound that unless one had studied mathematics to an exceedingly advanced level, the scattered stars in its sword manual would look like a tangled mess, impossible to make sense of.
How could Niu Tongtian have known that when Xu Yi said he had only a rudimentary grasp of mathematics, he wasn't bragging—he was being modest?
As soon as he unfurled the star chart, Xu Yi saw that it was extraordinary and was instantly absorbed in it.
To Xu Yi, that profound star chart was a series of interconnected mathematical problems. Each time he strung together a set of beads, he solved another riddle.
If the Green Demon King had been there, he would never have believed that in a mere moment, Xu Yi had deciphered the entire Hun Tian Sword manual save for the final style, which he had yet to piece together.
The last thirteen scattered stars represented that final style. Once he connected them, the entire Hun Tian Sword manual would be completely deciphered.
For most of the second half of the Spring Welcome Banquet, Xu Yi had been immersed in deciphering the Hun Tian Sword manual, but he had never found the key.
It wasn't until Remembering Cliff, when Niu Tongtian suddenly turned on him and joined forces with the twelve Golden Armored Demons to perform the Hun Tian Sword and trap Long Jingtian right before his eyes, that Xu Yi found his inspiration.
From then on, he continued unlocking the final thirteen stars while visualizing Niu Tongtian and the others performing the