So far it's an "Eh~", like why the Elf didn't pushed for an answer? If true name is something really really important, why she just let it go like that...
Definitely don't mind harem as many people get very upset with it but in honesty I'd rather have 3 wives then just toss my girl away after a while for a new one. People are so bullshit with the built in constraints of society. Marriage itself was basically legal ownership transference of women. Society still treats women like shit when they're so great. I love women what's wrong with loving more than one. (Only reason polygamy is illegal is insurance/medical greedy garbage)
Absolutely upset with the writing but I'll probably keep reading. MC refuses to bring childhood sweetheart on adventures cause "it's too dangerous". Didn't she die by staying in this town that is ON THE BORDER of the demon territory? Bullshit logic same for sexy elf girl. He calls her TOP SECRET true name that can control like her very life out loud in public? Then she's just like sure let's forget about it. Never tell this MC a secret he may just yell it out in public.