Efretta
William didn't intend to make full use of his Array Puppets, even though it was a skill common to Array Masters and wouldn't necessarily expose his true identity.
An Advanced Array Master could control a single Perfect Array Puppet or maybe even two at once, but any more than that would allude to the existence of a Perfect Array Master, which were few and far between across the entire Azures Continent.
In all of Blue Moon City, there was only one Array Master capable of creating Perfect Runes. Other than him, William had met only a few others that could reach the same level. If he had to guess, he would say that there were probably only a few dozen Perfect Array Masters in every Region.
Much like Tribulation Transcendence Cultivators, S-Ranked Mages, and other top-tier tradesmen, reaching such a level was incredibly difficult. Those who did were probably talented enough to Ascend, keeping the number consistently low.