In the webnovel this girl was my least favorite and I think that's still true in the manga. I like her but she's just not as interesting as the others imo.
He really needs to call up Rekka Namidare (from "I Saved Too Many Girls and Caused the Apocalypse) and learn how to prevent a war.
For those who don't know: Rekka comes from a "special bloodline" that pulls him into "save the heroine" plots where that story's hero failed. He ends up saving so many of them that they cause an intergalactic war over him. Yes, he saves alien princesses, angels, demons, even Leviathan from the "Leviathan and Bahamut" mythology. It's very funny.