I'm a little sad this series is over because I have enjoyed Percy, Annabeth, Grover, and all their other friends and family. It was great to see so many characters come out for the last battle with Kronos. It is often hard for an author to contain so many characters without overwhelming the reader but Riordan did a great job focusing on Percy and having everyone else come into his perspective. It was the best way to write the entire series and I for one am glad he did so. 
 You can't say these characters are really fleshed out but they are enjoyable enough and real enough for the young age group they've been catered too. I would recommend them as a fun fantasy story because no matter how many prophecies are tossed Percy, Annabeth or Grover's way, we always get a great adventure and a wonderful story.