After returning from the wilderness, Aphnora looked as though she had suffered something unspeakable. She was dazed and absent-minded.
Yu Sheng'an, on the other hand, looked thoroughly satisfied, though somewhat regretful.
First, the Infrasonic Wave he had placed high hopes on had produced rather poor results. Whether beasts or Orcs, they showed adverse reactions, but nothing too severe.
Yu Sheng'an guessed that it was probably because creatures in the multiverse generally possessed stronger constitutions.
It was said that a tiger's roar could frighten prey to death because it contained infrasonic waves.
In the multiverse, savage beasts comparable to tigers were everywhere. All kinds of creatures had probably evolved, more or less, the ability to resist infrasonic waves, so it was understandable that they were not very effective.
Even so, if used suddenly on the battlefield, it might still be able to interrupt spellcasting.
Second, Resonance had a rather narrow range of application. Yu Sheng'an found it difficult for Resonance to penetrate Magic defenses, and this world had countless methods of magical defense.
Therefore, this move could only be used after breaking through an enemy's defenses.
However, once the conditions were met, collapsing an entire city would be easy—provided one was willing to spend the Source Essence.
Third, Ultrasonic Cutting was essentially flame cutting.
However, due to the transmission characteristics of mechanical waves, it could be used for long-range attacks. As long as he was willing to consume Source Essence, it could achieve the effect of a laser cannon.
Finally, Yu Sheng'an considered Levitation Flight and Sonar Detection the most practical.
There was no need to elaborate on Levitation Flight.
Sonar Detection was especially suited for battlefield use. It would be an entirely new method of detection; what results it could achieve would have to wait for actual combat to test.