Hearing Alister's words, Zanna nodded her head, "I can defend the spirit realm from the Sword Hero. But if the Sword Hero requested reinforcements and teamed up with the other heroes, I would be rendered powerless against them."
"Make sure to arrive in time when I need your help."
Although Zanna was clingy and wanted to spend as much time as possible with Alister, she didn't want to restrict and control Alister's freedom so she wasn't against him leaving for training.
She had already guessed that Alister's purpose was likely to surpass Fantasia and become the strongest.
After all, she had assisted Alister in creating the God Slaying Magic which proved that Alister was ambitious enough to have the intention of killing and surpassing a god.
Since she had stayed in the Sea Of Chaos for ten thousand years, Zanna had already known the existence of other worlds and worlds that weren't under the jurisdiction of the Goddess of Fantasy.