so the title's left unresolved, and next episode there could either be an unnecessary killing, or a killing to prevent an unnecessary killing -- with the obvious question in the latter case of "was that a necessary killing?"
until recently the series has been war between humans and demons, and they go out of their way to convince the viewer that the villains (demons) really are inhuman: creatures incapable of feeling empathy toward anyone and therefore not worth your own empathy. and the heroes (at least in the ideal) are those who do exactly what's necessary, but no more, when it comes to violence. i don't know that the story can veer too far from that ideal framing of heroism without losing its charm, but they may be setting up to challenge that framing of villainy.
also, seems it's becoming a pattern that Fern's opponents are caught off-guard by her speed & stamina. when she fought the demon in episode 10, that was explained as her suppressing her mana, and the demon being careless/overconfident against such a technique. but here in ep 20 everyone is familiar with mana suppression: that Fern's overwhelming experienced mages with just raw speed/stamina has me suspicious.
The episode where Frieren talks about mana suppression she mentions doing mana exercises, and after 1000 years that's why she has so much. Fern has been training the same way for like 20 years now so she probably has a pretty huge mana pool compared to the average mage. She also only uses basic attack and defense magic, so she's almost like a demon in that she's mastered a single specific talent. In this case that talent is rapid firing dozens of basic attack spells at once.
