▁that ▁players ▁maintain ▁their ▁own ▁map ▁by ▁annot ating ▁( with ▁the ▁st yl us ) ▁a ▁small ▁map ▁displayed ▁on ▁the ▁D S ' s ▁touch screen . ▁The ▁player ▁is ▁free ▁to ▁map ▁accur ately ▁or ▁ha ph az ard ly . ▁However , ▁the ▁player ▁cannot ▁draw ▁their ▁own ▁symbols , ▁and ▁must ▁instead ▁use ▁the ▁game ' s ▁limited ▁set ▁of ▁pre - des igned ▁symbols . ▁The ▁game ▁also ▁limits ▁the ▁number ▁of ▁symbols ▁that ▁can ▁be ▁used ▁for ▁each ▁level ▁map . ▁ ▁In ▁addition ▁to ▁normal ▁random ▁enc oun ters , ▁the ▁player ▁must ▁overcome ▁" FO Es " ▁( Field ▁On ▁En em ies ), ▁which ▁are ▁exception ally ▁powerful ▁mon sters ▁which ▁w ander ▁around ▁the ▁d unge on ▁in ▁much ▁the ▁same ▁way ▁as ▁the ▁player ' s ▁party , ▁adv ancing ▁whenever ▁the ▁player ▁does . ▁The ▁A I ▁of ▁FO Es ▁var ies , ▁but ▁most ▁will ▁w ander ▁the ▁d unge on ▁in ▁a ▁set ▁circular ▁path ▁until ▁they ▁sense ▁the ▁player ' s ▁party , ▁after ▁which ▁they ▁will ▁move ▁directly ▁towards ▁the ▁party . ▁If ▁the ▁player ▁enc oun ters ▁an ▁FO E ▁in ▁an ▁area ▁with ▁multiple ▁FO Es , ▁it ▁is ▁possible ▁for ▁a ▁second ▁or ▁even ▁third ▁FO E ▁to ▁join ▁the ▁battle ▁if ▁it ▁reaches ▁the ▁party ▁before ▁they ▁defeat ▁the ▁first ▁one . ▁ ▁Like ▁most ▁early ▁R PG s , ▁E tri an ▁Od ys sey ▁uses ▁custom ▁characters ▁from ▁a ▁number