- Ascended Fanon: Of a sort. A popular fan-created mock cover for The Blood of Olympus was licensed by Disney to appear as a poster in the Wal-Mart exclusive edition of the book.
- Fan Nickname: Camp Purple/Camp Bizarro/Camp More-Badass-Than-Thou for the Roman demigod camp, Camp Jupiter.
- I Knew It!: Acclaimed fanartist Viria drew this picture four months before House of Hades with Calypso's reappearance and romance with Leo was released.
- Before Son of Neptune, many viewers speculated who the other four of the seven were. Annabeth was correctly guessed - but Reyna was another common guess as well. In a bizarre way, Reyna turned out to be one of the most important characters in the series and gets to be a viewpoint character in the final book.
- Name's the Same: A Power Trio with members named Piper and Leo.
- Promoted Fanboy: Viria, one of the most popular fan artists for the series, ended up getting commissioned to make official character portraits on Rick Riordan's website.
- Trolling Creator: Riordan dedicated the fourth book House of Hades, to the readers. It says "To my wonderful readers: Sorry about that last cliff-hanger. Well, no, not really. HAHAHAHA. But seriously, I love you guys."
- He apologizes for this in the dedication for the fifth book, but says "I'll try to avoid cliffhangers in this book. Well, except for maybe a few small ones... because I love you guys."
- The Wiki Rule: Riordan Wiki covers The Heroes of Olympus.
Trivia / The Heroes of Olympus