When Akiol launched the {Hyperburst}, he found out that the undead are incapable of restoring any pieces of their body destroyed to a fine degree or erased. By connection that would make Givale, the dragon capable of erasing space, one of the few tools they had to permanently rid of any undead.
However, Akiol made it clear she wasn't to entirely erase any undead just yet. The moment the undead realize that they had a tool that could bypass the Territory, she would immediately be swarmed and possibly killed. Thus also knocking out Akiol and Mira from the fight. It would be a trade of fighters, one Akiol wanted to avoid.
Thus when he sent Givale to handle the flying enemies he kept one rule in her mind: "Do not erase them entirely."
