. ▁He ▁then ▁accepts ▁death , ▁willing ▁to ▁An nab eth ▁his ▁laptop ▁filled ▁with ▁thousands ▁of ▁years ▁of ▁notes ▁and ▁ideas . ▁In ▁death , ▁he ▁becomes ▁the ▁Under world ' s ▁architect ▁and ▁is ▁allowed ▁to ▁visit ▁I car us ▁and ▁P erd ix ▁on ▁week ends . ▁ ▁E ury tion ▁– ▁A ▁son ▁of ▁A res ▁who ▁works ▁on ▁G ery on ' s ▁ran ch . ▁He ▁appears ▁in ▁The ▁Battle ▁of ▁the ▁Lab yr inth ▁and ▁helps ▁Per cy ▁and ▁An nab eth ▁locate ▁He pha est us . ▁ ▁Hal cy on ▁Green ▁– ▁A ▁son ▁of ▁Apol lo ▁gift ed ▁with ▁prop he cy ▁and ▁under ▁" house ▁arrest " ▁for ▁reve aling ▁to ▁a ▁young ▁woman ▁her ▁fate . ▁He ▁gives ▁his ▁life ▁to ▁save ▁Luke ▁Cast ellan ▁and ▁Th alia ▁Grace ▁from ▁the ▁Le uc ro ta e ▁and ▁his ▁burning ▁m ansion ▁in ▁The ▁Di ary ▁of ▁Luke ▁Cast ellan ▁( part ▁of ▁The ▁Dem ig od ▁Di aries ). ▁ ▁Her acles / Her cules ▁– ▁ ▁A ▁famous ▁Greek ▁hero , ▁and ▁the ▁son ▁of ▁Ze us ▁and ▁Alc men e . ▁Following ▁his ▁death , ▁Ze us ▁brought ▁him ▁up ▁to ▁Mount ▁Olymp us ▁to ▁live ▁with ▁him ▁and ▁he ▁is ▁engaged ▁to ▁Heb e . ▁Her acles ▁was ▁mentioned ▁but ▁did ▁not ▁appear ▁in ▁the ▁first ▁book ▁series , ▁usually ▁when ▁mon sters ▁that ▁he ▁had ▁fought ▁show ▁up ▁to ▁trouble ▁Per cy . ▁In ▁The ▁T itan