Welcome To Japan, Elf-San - Chapter 17

Toru*: “Woha, don’t answer me! I’m a government employee.“

TL: “I don’t know what this means.“

Here’s the thing: MC introduced her as relative. She looks young. Possibly underage*². Didn’t help she wore a school uniform the first time.
Toru, as government employee, is probably beholden to report crimes he knows of.
So, MC saying they are together would mean, in Torus eyes, MC confessing he has an incestuous relationship with a minor outside of a loving reciprocal relationship (as she isn’t long enough in Japan to establish that). So, Toru would be obligated to report it to the police, which then had to start an investigation.
But if MC doesn’t say that, Toru can always claim he didn’t know, he speculated , but didn’t know.
And saying they aren’t related would open up another can of worms, as MC would then have to explain who it comes he lives together with an underage foreigner. (Sex) Trafficking comes into mind.

Yes, I know she’s 100 years old, MC knows that, too. But it isn’t as he could tell others. Both would end up in a research facility.




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*=The man of the married couple
*²=This Japan, not anywhere else in the world. Hence age of consent has a different meaning.