Octavian

Fiona Verde

In The Son of Neptune,  when Percy first meets Octavian, this happens:

"You remind me of someone,"  said Percy.  "I can't remember who."
"Possibly my name sake, Octavian-Augustus Caesar.  Everyone says I bear a remarkable resemblance."
Percy didn't think that was it, but he couldn't pin down the memory.

The question is, who does Octavian remind Percy of?
Well, I read part of a fan fiction that involves Octavian going to Camp Half Blood.  Everyone there is staring at him.  He finds out that it is because he looks exactly like Luke, without a scar.
What if Luke and Octavian are some how related, like Sammy and Leo?  Obviously they can't be grandfather and grandson, but maybe they are cousins.  Luke's mom could have a sibling, who is one of Octavian's parents.  We don't know Octavian's last name. Could it be Castellan?
The only thing wrong with this theory is, Annabeth didn't have a reaction when she saw Octavian, not one of recognition.  If he looked like Luke, wouldn't she have a reaction, even if she was distracted with Percy? Even if Octavian looked like someone else, Annabeth would have noticed, after she got over the excitement of seeing Percy.
Unfortunately Percy has not brought up this subject again, so we do not have any more information.  But if Annabeth doesn't think Octavian looks familiar, and Percy does, than Percy must have seen this look-alike  when they weren't adventuring together.
Hmm... Percy delivered the master bolt to Olympus without Annabeth.  But she's been there a lot of other times, so you would think she saw all the same people.
Annabeth wasn't there for the quest to find Artemis, of course.  I can't think of anyone who looks like Octavian from that adventure, although I lost the book, and haven't read it in more than a year, so I may have missed someone.
Percy visited Ogygia by himself, but the only person there was Calypso.
He also went to blow up the Princess Andromeda with only Beckendorf.  Maybe there was a demigod who looked like Octavian on board.
Of course, it could be some random person who went to one of Percy's schools.
Who knows, maybe this is nothing, just Percy's memories being messed with more than we thought. Although I doubt Rick Riordan would have just said that, and then made it nothing.

If you can think of any other times that Percy might have seen someone Annabeth didn't, or you can think of someone else who might resemble Octavian (and is around the right age) please leave a comment.