@Kinsei translation question: Would Nanaka's spell happen to be "Raigeki"
Destroys all enemy monsters sounds awfully like the spell effect of the Yu-Gi-Oh card.
Oho! That's an excellent catch. The "Turn End" in the commentary should've tipped me off. Too many years without playing YGO. The text is just the English "Thunder Bolt" written in katakana, which could easily just be a generic spell name, but it is also the Japanese name for Raigeki and is most assuredly the reference it was going for. She didn't quote the effect text exactly though...
Hehehe...So persistentー!What a foolish fellow...!
Your fate has already come to an end!Go on and accept that fate!*Dash!*Oh shi-!?You are way too good at fleeing!Oyo? Anna-taso?Ah! One of those joined with me in alliance...!
Nanaka...!Lend me a hand in apprehending that bountyー!Okayー!
Here it comes!Magic Card Activate!Na!Gyaaa*Brzap*We are the cutest, the strongestMagical Girlsー★Nya nya
Nya~ ♪Magical girls!
They're so cool nyaー!Raigeki!Destroy all opponent's monsters!