In comparison, deriving a Wind-type spell was much simpler. In Merlin's Awareness, he had constructed Zero-level spell Gale, First-level spell Wind of Freedom, Second-level spell Light Breeze, and Third-level spell Shadow Gust.
These spells were speed enhancers and had distinctive features. If Merlin wanted to derive a new Fourth-level spell, it would need to have sufficient speed.
Moreover, a Fourth-level Wind-type spell had another feature, which was to enable flight. Currently, Merlin could only rely on the Flying casting tool to fly, but he was no match for Spell Casters above the Fourth-level in terms of speed.
The exception was if Merlin could merge with Flash Wind. However, this would consume too much energy. Flash Wind was not meant for speeding up journeys, but for battle. It was able to increase one's speed countless times in an instant.
