▁a ▁floor ▁in ▁the ▁main ▁studio ▁for ▁Jason , ▁Leo , ▁and ▁Pi per ▁to ▁walk ▁on . ▁M ell ie ▁does ▁not ▁like ▁them ▁because ▁the ▁har p ies ▁are ▁mean ▁sudden ▁g ust s , ▁whereas ▁the ▁a ura e ▁are ▁all ▁gentle ▁b ree zes . ▁ ▁C ela eno ▁– ▁A ▁Har py ▁whose ▁name ▁means ▁" the ▁dark ." ▁She ▁is ▁a ▁member ▁of ▁Camp ▁Half - B lo od ' s ▁" C lean ing ▁Har p ies ." ▁C ela eno ▁is ▁also ▁known ▁as ▁Pod ar ge ▁( which ▁means ▁" f le et - foot "). ▁ ▁El la ▁– ▁A ▁Har py ▁who ▁appears ▁in ▁The ▁Son ▁of ▁Ne pt une . ▁She ▁has ▁red ▁hair ▁and ▁fe athers , ▁grey ▁eyes , ▁and ▁a ▁b ony ▁structure . ▁She ▁has ▁extensive ▁knowledge ▁about ▁the ▁Rom ans ▁and ▁their ▁culture . ▁El la ▁is ▁very ▁valuable ▁to ▁the ▁enemy ▁side ▁as ▁she ▁might ▁have ▁knowledge ▁of ▁several ▁scroll s ▁of ▁prop he cies . ▁She ▁has ▁memor ized ▁a ▁lot ▁of ▁books , ▁and ▁often ▁rec ites ▁a ▁few ▁prop he cies ▁from ▁the ▁Sy b ill ine ▁books ▁that ▁Oct av ian ▁des per ately ▁wants . ▁It ▁is ▁mentioned ▁towards ▁the ▁end ▁of ▁The ▁Son ▁of ▁Ne pt une , ▁that ▁El la ▁needed ▁to ▁be ▁hidden ▁from ▁Oct av ian ▁because ▁of ▁this ▁important ▁knowledge . ▁She ▁was ▁one ▁of ▁the ▁Har p ies ▁who ▁was ▁trying ▁to ▁tor ment