I kinda forgot about this moment until now, haven't read the books in a while.
In all honesty, if the books were aimed towards an older audience, then I would love to see Percy use this power more, and for good.
Honestly, he went from being this kid new to his powers defeating Ares, to this teen who's controlled the insides of a literal god.
I need more dark Percy, but he's still good, still loyal. He uses these new dark powers t protect those he cares about.
Percy is honestly so dam powerful. Many characters point this out, both god and mortal, through the books.
I would just absolutely love to see him use his manipulation of almost any liquid for good.
Also, question; can he sense if someone has like a disease or something in their blood?
That would and could be interesting. Imagine he helped Apollo kids or something. After learning he can control blood, he helps the best he can to try and save a camper dying from blood loss.