Sophie who's engaged with MC due to MC's friend's life is in danger and their engagement is the only reason Allen is still alive.
In illustrations (Vol. 4) nympho foreigner who looks just like her (Sophie) is having a gangbang, when I start reading the serie, I also thought she was Sophie.
Also Allen and Sophie don't have a relationship, they are just sex buddies, so NTR once again is impossible, and even more she and Allen stop having sex after Esther broke up with him but as non readers though the gangbang girl is sophie, they think she's fucking with lots of guys while being Tanaka's "fiance", when Sophie (who works as and idol in MC city) wanted to retrieve her fans who prefer to fuck nympho than go to her concerts, so she went to the same bath where the other girl was getting fucked but as soon as she saw semen she run away.
4) Some call her slut just because of MC "strenght" and that she would dump him nor even care about him if he was weaker, which is false as we see when Sophia (maid) finds her diary in the trash bin, and reads about their Dragon Hunt quest, and we found out why she became an adventurer and how she fell in love with Tanaka no because he was strong (she knows a lot of strong people, amongst them Fahren the strongest magician in kingdom) or have a bigger dick as some idiots but 'cause of his bravery. How he didn't abandoned her even against an ancient dragon and more shit.
Then comes the domino effect, 1 guy says girls are bitches (not sexuality, but personality) then people starts to say NTR without real knowledge, other people read the reviews and only accept one sided part -NTR- and automatically say it's NTR despite other people explaining the story, and the chain keeps growing.
Serie is written as a parody so, no matter how much MC wants to have sex, he's still a virgin.
Just like OPM no matter how much MC wants to feel the thrill of battle, he will always easily win.
Want to know what is happening? How some people even when someone explains them the serie, they keep saying NTR despite beenthe same ones who are asking what's happening? look for tanaka in animesuki forums and you will know all the NTR is fake shit.
Besides, how would you call it when a female lead that confessed her love for the MC keeps fucking guys around? One-sided NTR?
Esther haven't had sex since she broke with Allen in Dragon Extermination Arc (Vol. 1) and the proof comes in Succubus Arc (6 months after DE Arc) where she falls ill and a trap who is a half-succubus like her tells them that succubus need semen to survive or they die, and that she had been "thirsty" for a lot of time