I'm not 100%, the last time i read this Manwha was months ago, but I think he mentioned usually theres just one stronger gene taking over, so a shapeshifter, immortal child would probably take only one of their parents abilities in normal cases.
Why they are hiding it? Who knows, maybe the time to mention it never came up, they are both part of those organisations, maybe its against their rules to tell their families, could be anything
and Im curious about what they mean by the "New Experiment" of creating mixed blood and end up creating a monster.
and, our MC live a very normal life so no wonder hes so out of touch with the super human things. he thinks that mixed blood like him is a normal things.
Him being a good son to his parents is so cute. He is so optimistic and willing to do anything his parents ask without complaining. Did he ever has rebel era? lolol
but why would his parents hide their identity, and if his parents could have a mixed lineage, why there are no other people like him? I mean there would be chance of people like his parents tho.