Responses

Oh, it's because Harry, as the author portrays is a demon who have lived for more than 2,000 years and he detests reliving his desires by having skinship with humans. So, that just meant that he lived as a virgin for how many years. And the nickname 'grandpa' is what Yveria called him when she knew his real age.
(๑❛ᴗ❛๑)
Another Virgin Grandpa detected(≧∀≦)