|“||Jason Grace, the West Wind has been called many things . . . warm, gentle, life-giving, and devilishly handsome. But I have never been called startling. I leave that crass behavior to my gusty brethren in the north.||”|
Favonius is the Roman counterpart of the wind god, Zephyrus. In Roman mythology, Favonius held dominion over plants and flowers. He also served Cupid, the god of love, after he was threatened by Apollo for the accidental murder of Hyacinthus.
While trying to find the scepter of Diocletian in Dalmatia, Jason Grace and Nico di Angelo come across the winged god Favonius. The god explains to them that the scepter was no longer there as it had been taken by his master. Jason asks if by master the god meant Aeolus, but Nico realizes that he was referring to Cupid. Favonius congratulates Nico on his deduction, commenting that he always knew the son of Hades would return to look upon Cupid's face. Jason questions Nico on the meaning of the statement which the latter avoids having to giving an answer to. After Favonius remarks that the "one Nico cared for most" plunged into Tartarus, Jason assumes that the god was referring to Nico's rumored crush on Annabeth Chase.
Favonius then takes Jason and Nico before Cupid, all the while recounting the story about how he had killed Hyacinthus and was forced into the service of the god of love. Upon Cupid's arrival, Favonius gives Nico a warning about dealing with Cupid before leaving the demigod in the presence of the said god. Soon after, it is revealed that the person that Nico had a crush on and the "one whom he cared for most" was Percy, and not Annabeth, after all.
- The name Favonius, meaning "favorable", was also a common Roman name.