A spy seems like one of the more tame "bad guy" options they could have gone with... I guess that's better than the stereotypical evil guy you'd expect
300?!? I thought there were like 50 of them. It's impressive that many could go in the town and not destroy more than a single food stand.
Focusing on lightning magic does make sense, but they're about to find out why you shouldn't put all your eggs in one basket
As others mentioned, I wonder how chaotic the battle will be. I can't imagine these kids being able to learn to tell friend from foe so quickly.... Maybe Reisu will just take the flock and tell the other soldiers to just leave it to them

It will also be tough to get them to fight, but not eat their kill. Definitely don't want to let them get used to eating humans.
Maybe Reisu will just solo them
