Man, his pathetic behavior whenever it comes to that devil girl makes me sick. He knows full well what's up, he knows her malicious intentions, he knows she's full of crap, he knows she's not that girl at all, yet he acts like this all the same, being taken advantage of for no real reason and letting royal pains in the ass go to cause more trouble and suffering.
Just kill her already. What I don't get is why he doesn't just go to a parallel universe and coax her to go back to his universe with him. Clearly it's possible and a million times easier than finding that whatever treasure since he's already done it before. Hell, not bringing the older version back with him was just bullshit in the first place, why not bring her and his granddaughter and whoever else back with him that doesn't exist in his own universe? Won't cause any problems.
It's frankly frustrating how the author paints him out to be a selfish bastard who knows the rules of the world yet at the same time makes him weirdly obsessed with shounen manga moral ideals like having to save everyone and anyone in his way and being a doormat who fails to grasp the idea that rooting out the weeds are necessary to prevent further harm.