▁is ▁related ▁to ▁virt ually ▁every ▁character ▁and ▁creature ▁in ▁Greek ▁myth ology ▁through ▁his ▁father ▁P ose id on , ▁T ys on ▁is ▁one ▁of ▁the ▁only ▁be ings ▁whom ▁he ▁acknowled ges ▁as ▁family . ▁Per cy ▁first ▁met ▁T ys on ▁at ▁a ▁school ▁called ▁Mer iw ether ▁P rep , ▁and ▁did ▁not ▁learn ▁of ▁their ▁relationship ▁until ▁much ▁later . ▁Per cy ▁is ▁also ▁dist antly ▁related ▁to ▁horses , ▁p eg asi , ▁some ▁other ▁mon sters , ▁and ▁numerous ▁gods ▁and ▁dem ig ods ▁through ▁his ▁father . ▁Sign ific ant ▁examples ▁of ▁this ▁would ▁be ▁that ▁he ▁is ▁techn ically ▁a ▁grand son ▁of ▁K ron os , ▁nep hew ▁to ▁H ades , ▁Ze us , ▁and ▁numerous ▁other ▁Olymp ians ▁as ▁well ▁as ▁the ▁half - ne p hew ▁of ▁Ch ir on . ▁ ▁Fri ends ▁ ▁Per cy ' s ▁oldest ▁friend ▁is ▁Gro ver ▁Under wood , ▁a ▁sat yr ▁originally ▁task ed ▁with ▁protect ing ▁him ▁and ▁bringing ▁him ▁safely ▁to ▁Camp ▁Half - B lo od . ▁His ▁next - old est ▁friend ▁is ▁An nab eth ▁Ch ase , ▁whom ▁he ▁meets ▁when ▁she ▁helps ▁nur se ▁him ▁back ▁to ▁health ▁after ▁his ▁first ▁fight ▁with ▁the ▁Min ota ur . ▁The ▁two ▁accomp any ▁him ▁on ▁his ▁first , ▁and ▁most ▁of ▁his ▁subsequent , ▁qu ests . ▁ ▁Per cy ▁is ▁also ▁close ▁to ▁many ▁other ▁characters ▁in ▁the ▁book ▁series . ▁His ▁closest