Aeternae are bone-covered giants who gain strength and gather more bones whenever they are killed.
The Nico di Angelo Adventures
The Sun and the Star: A Nico di Angelo Adventure
When Nico di Angelo and Will Solace are searching Tartarus for Bob, the son of Hades inadvertently summons two aeternae when they are corned by a pack of Cynocephali. The giants kill the dog men and beg the demigods to kill them and threaten to eat them when the 6 refuse. Small Bob kills the pair and the demigods vow to never bring it up again.
| The Nico di Angelo Adventures | |
| Books: | The Sun and the Star: A Nico di Angelo Adventure | The Court of the Dead |
| Main Characters: | Nico di Angelo | Will Solace | Hazel Levesque |
| Secondary Characters: | Screech-Bling | Hiss-Majesty | Iapetus | Chiron | Gorgyra | Small Bob |
| Minor Characters: | Kayla Knowles | Austin Lake | Rachel Elizabeth Dare | Percy Jackson | Annabeth Chase | Sally Jackson | Estelle Blofis | Meg McCaffrey | Epiales | Echidna | Menoetes | Amphithemis | Maria di Angelo | Bianca di Angelo | Piper McLean | Shel |
| Gods: | Dionysus | Apollo | Hypnos | Nemesis | Acheron | Persephone | Hades |
| Giants: | Otis | Ephialtes |
| Primordial Gods: | Nyx | Tartarus | Chaos | Gaea |
| Monsters and Magical Creatures: | Nymph | Cacodemon | Troglodyte | Demon | Chimera | Empousa | Stymphalian Birds | Cynocephali | Telekhine | Basilisk | Manticore | Pegasus | Aetera | Mania | Minotaur |
| Related Content: | Rick Riordan | Mark Oshiro | The Trials of Apollo |