It'd be pretty easy to answer, because the answer is always going to be >Yes.
Since the enemies are either always aggressors of a comical nature, or they at least involve you in some way because you're allied with someone ELSE fighting against an aggressor of a comical nature, excepting the few "good guy" enemies that end up going turncoat (like Eir) or not being a problem passively. Askr then justifies the kills and conquering simply because of their jurisdiction over gates and how it could fuck EVERYONE up if they failed.
Seriously, we have>Book 1, Veronica and Bruno
Bruno fucked off and his curse isn't bothering us, and Veronica is almost 100% an ally at this point. Otherwise we just bullied her and she got kidnapped. She did attack Askr though, so justified.>Book 2, Surtr and co.
Surtr was the definition of violent and evil. His family were following orders, so it was Surtr's fault. Justified action. Loki was just smarmy and vaguely neutral.>Book 3, Hel and co.
Literal zombie hellslaves and all consuming death. Justified action.>Book 4, Freyja and co.
Freyja was trying to merge nightmares with reality and catch us in an everlasting nightmare. Fuck her, justified action. Cum fairies were following orders.
And now with Book 5, we've got Fafnir who immediately began as an aggressor, and then Eitri who exacerbated the issues. Justified action. And not to forget Otr.