As mentioned in the game itself, Poseidon is the god of earthquakes. He’s got a body count that puts epidemics to shame.
Whereas Hades, god of the underworld, is just known for minding his own business and lurking invisibly.
So if a child of Hades takes after him, it would not be as a killer, but as a master of hide and seek. Hades is the god that is sneakier than Hermes the god of thieves.
But even if the MC took after Hades in the sneakiness department, the MC was raised by Hades for 6 years.
Or if the MC is studious, so what? The MC was raised by freaking Athena, the idea that she’d put up with academic slacking boggles the mind.
Or that matter, the MC is a perpetual reincarnate, why believe they are a tabala rasa at birth when their soul has billions of years experience under its belt?