Answer:
.......
Explanation:
Factory, easy it shall be

The harmonic frequency refers to the resonant frequency that is an integral multiple of the fundamental frequency, harmonics are usually simple sinusoidal oscillation at a single frequency. where as Resonance frequency are frequencies that are not necessarily sinosudal or integral multiple of fundamental frequency and it may have complex oscillations made up of multiple harmonics ~
It's like if you play a piano with a single key, it will show harmonic frequency, but if you use multiple keys at a time it may show Resonance.
Foreshadowing and metaphor because it foreshadows what will happen next (how they both got attacked by bob)
The word you're looking for is prowess, however you didn't post a list. Prowess means superior skill, strength, or ability. Other similar words are expertise, aptitude, and mastery.