Could you imagine? I don’t mean mental illnesses such as anxiety or depression, panic attacks, OCD, etc. because I assume that many would develop such condition based on being attacked by monsters on a day to day basis as children as well as (probably) abandonment issues due to an absent parent.
I rather mean lot descriptions of physical disabilities/illnesses? That leaves such a powerful image in my head? Yes, ambrosia/nectar could potentially fix a lot of these issues but what if some stuff remains permanent?
Percy breaking his hand and being more prone to develop arthritis in his hands due to sword fights? Also having broken bones comes with the risk of chronic pains
Annabeth having cluster headaches? These are one of the most nasty type of headaches. Coming in intervals and your eye feels like it’s ready to pop? Dizziness, trouble with vision, etc?
Grover is the closest of being described of having a physical disability? I mean it disappears as soon as he reaches CHB but it’s still worth mentioning. But what would be if a satyr loses his sense of smell? No longer being able to smell the pollutions of humans is a plus, sure. But the important ability of sensing demigods? Feeling natures balance? The link to Percy?
Can you imagine Nico having Ehlers-Danlos (EDS)? The condition with overstretched skin and tissue? And after a round of shadow traveling his knee pops out? Or his hips are dislocated?
Clarisse suffering from endometriosis followed by the worst type of period cramps during her menstruation? Constant pain during bowels or urination?
Bianca (because fuck you Rick!) having the worst case of atopic dermatitis and being allergic to bunch of stuff in the underworld and just scratching the living shit out of her until her skin bleeds?
Like fuuuuck. Of course not every illness listed goes that way but it could be a possibility.
Also interesting: demigods with autism?