Well honestly, I wouldn't be surprised if she kept downing him and supressing his potential just to keep him around because she's in love with him and/or knows his true potential and has an inferiority complex about it. The great Hero is weaker.Same premise as "A Sword Master Childhood Friend Power Harassed Me Harshly", but the hero is extra shitty, not tsundere.
Honestly, I'm shocked someone can actually make it work without annoying the shit out of me, because mc would go 'That's normal' for the coming 5000 Chapters, instead this dude is actually using his brain truly deserving of 'Sage' ò_óNow this how you do "I'm actually OP" by making the abuse sounds realistic.
He didn't get any chance to check himself and had been told to kept his power at bay.
Not "oh this is normal" "i haven't checked yet even if I had the time no do so"
Or we can just accept the fact that weaboos will use Japanese gratuitously, and westaboos will use English all the same. Then again, this kind of thinking would win you a no-prize from Stan Lee and Marvel back in the dayBack in the day, in many parts of the world, commoners got family names based on external factors. Profession was an extremely common cause, and it stuck even if it had been many generations since Smith had been a (village) smith. Location names are rather typical as well. Locations had solid names before commoners. A farmstead could have had a name, and the farmer could then take the farm's name as his own family name. Depending on the culture, a person's visage or psysique could result in a name. In some cultures, before solid last names, a person could introduce him/herself by telling who their father was, like "Gary, John's son". That then turned into Johnson, when the family name became solid. Of course when laws started to demand every person must have a surname, they were just invented or selected from wherever.
So, all in all, we can assume Haru is Haru Traitor because his forefather was a known traitor, and the cruelty of the society demanded the progeny carry that disgraceful name.