The spear hurled at Wizard Reed must have been thrown by Milo.
He was Kuyi Tulan's right-hand man, so naturally, he would be the first to understand Kuyi Tulan's orders.
Milo's proficiency in the Exchange Spell allowed him to conjure large quantities of metallic objects from thin air. He had already demonstrated this when dealing with Witch Bigas, and he now threw these spears partly as a test and partly to establish coordinates.
Every Alchemy Array requires a fixed orientation. Combined with specific Alchemy Equations, the rudimentary framework of the array could be established.
Through the infusion of Spirit Power by the spellcaster, the Alchemy Array could then operate freely. That is when an Alchemy Array truly forms.
