"This is insane!" Seeing Jiang Hai's movements, several onlooking soul engineers exchanged bewildered glances. They also used firebird down when crafting flying soul tools, but they would never be mad enough to engrave a soul tool array on every single feather. Even if they were only Level 1 core arrays, engraving over ten thousand of them would drive anyone out of their mind, wouldn't it?
Moreover, although the firebird down had been plated with heavenly fire meteoric iron, it remained incredibly soft. Engraving soul tool arrays on it was an exacting test of a soul engineer's skill. Soul engineers below Level 3 could not even engrave arrays on it.
Yet as Jiang Hai's hands danced, silver light flashed, and the azure silver dragon on his engraving knife seemed to come alive, swiftly carving one core array after another.
The longer they watched, the more astonished everyone became.
"He... he's actually engraving combination arrays! With this much firebird down, can he remember it all clearly?" After a while, the array beneath Jiang Hai's hands changed. Recognizing his intent, several of them cried out in shock.
The arrays Jiang Hai engraved into the firebird down were not all of the same kind. Instead, they were of several kinds that could be combined with one another. Although this involved only arranging and combining different arrays, it more than doubled the demands on the soul engineer. Combining and arranging so many arrays also required a truly terrifying memory. Even Zhen Weiding had taken half a month to complete this step when crafting the Vermilion Bird Wings, yet Jiang Hai intended to finish it in a single day. A heart mirror appeared within his mind, its surface displaying the arrangement of each feather of firebird down and the combinations of their arrays. The flame of