▁was ▁hunting ▁because ▁it ▁could ▁destroy ▁Olymp us . ▁She / He ▁appears ▁in ▁The ▁T itan ' s ▁Cur se ▁and ▁The ▁Last ▁Olymp ian . ▁ ▁Orth rus ▁– ▁A ▁two - head ed ▁dog ▁owned ▁by ▁G ery on ▁and ▁brother ▁to ▁Cer ber us . ▁ ▁Peg as us ▁– ▁Wing ed ▁horses ▁that ▁are ▁named ▁after ▁the ▁original ▁mount ▁of ▁B eller oph on ▁that ▁was ▁born ▁from ▁the ▁blood ▁of ▁Med usa . ▁ ▁Black jack ▁– ▁A ▁pure ▁black ▁Peg as us ▁and ▁Per cy ' s ▁loyal ▁friend . ▁He ▁is ▁first ▁introduced ▁in ▁the ▁second ▁book ▁The ▁Sea ▁of ▁Mon sters ▁on ▁the ▁Princess ▁And rom eda ▁where ▁Per cy ▁res cu ed ▁him ▁from ▁K ron os ' s ▁min ions . ▁Ever ▁since ▁then , ▁Black jack ▁has ▁felt ▁like ▁he ▁has ▁to ▁pay ▁Per cy ▁back ▁for ▁saving ▁him ▁and ▁he ▁does ▁whatever ▁Per cy ▁asks ▁calling ▁him ▁" b oss ." ▁He ▁is ▁seen ▁in ▁The ▁Blood ▁of ▁Olymp us ▁deliver ing ▁the ▁Ath ena ▁Par then os ▁to ▁Camp ▁Half - B lo od . ▁ ▁Gu ido ▁– ▁A ▁light ▁gray ▁and ▁white ▁Peg as us ▁who ▁is ▁friends ▁with ▁Black jack . ▁In ▁The ▁Last ▁Olymp ian , ▁Gu ido ▁and ▁P ork pie ▁a ided ▁Per cy ▁and ▁Black jack ▁in ▁the ▁Battle ▁of ▁Manh attan . ▁Gu ido ▁later ▁adopt s ▁Re yna ▁for ▁his ▁human ▁after ▁the ▁Gi ant ▁War . ▁ ▁P ork