Magic and Powers
Percy Jackson has a fixed amount of powers that he can do. He can just be creative and explore his limits with water. Also water is the only thing that he can use his powers with and draw power from.
Harry Potter can learn how to do about anything other than trying to raise the dead. However the only fallback is that he needs to have a wand to channel his powers (it is possible to do magic without a wand but it is unfocused). A powerful wizard can do magic without speaking but most need to be able to speak to use magic.
Eragon Shadeslayer has powers that are based from the ancient language. His magical powers are limited to both his vocabulary in the ancient language and his strength. Magic consumes energy so that if you try to do something like lift a mountain it will consume your strength and kill you. This is my favorite magic because of the limitations on the magician.
If the three fought using only their magic and Percy was standing in water, especially ocean water I believe that it would be pretty much a tie between the three. Only creative magic would ultimately win.
Who do you think would win? Vote or leave a comment.