Absolute Zero was a platinum-tier ice-elemental spell, and it was not only that. The essence of the spell was to control magical elements; it used space and time to freeze them. It was considered a fusion spell because the Golden Flash had that spell. Therefore, Watson was very familiar with it.
"You mastered a high-tier spell? Absolute Zero?"
Sylvan seemed a little surprised. Watson, he thought, was already excellent enough to be on the verge of platinum at that age. He had not expected Watson to be so knowledgeable about platinum-tier spells. He had underestimated his adversary. Unfortunately, he did not realize it until it was too late.