It'll be fine. Iruma will not be smelled out as he will eventually be revealed to be a human-demon hybrid and gramps is actually his gramps, with a sad story of how his real parents died and gramps sending him to the human world to protect him. His ability survive anything will be revealed to be an actual ability, along with other peculiarities he has displayed.
Nah, his parents are obviously demons who decided to live in the human world. And clearly they're Primal ones, too, worse than even Kirio. I mean, their wanton irresponsibility and neglect of their son manages to disturb other demons who hear about it. See: Bachiko's reaction when Iruma mentioned how often they'd put him into life-threatening situations.
...I say that jokingly, but the more I think on it, the more it makes a scary amount of sense.
