First,you must seperate them so it wont cost in healing herbs
Second,Just keep Pietro doing the skill "Dragon Saber"(you can learn it Lvl.22 and up)
Third Just keep Kai(the second form of Narcia to heal by the healing herbs(hint buy as
many as you can the Forest Twig and Forest shower)and let Kai attack sometime so they can
easily be defeated.

-Prince(Philippines)

First you must have the melia orb (get it at the old lady with many cats in popolocrois
city) and get an offensive orb like the zappa orb then summon melia and an offensive orb
then use melia's clarity to recieve 1-5 damages (there's no damage reductions in wild
monsters so use it only on bosses) only and enfeeblement to lower enemies' attack (and
defense i guess)then kill the first robot,then 2nd and last robot

I finish it in one battle without the using much healing herbs because of melia's spells

Oh and one thing, i recommend not to use melia to attack just keep using spells to refresh
the buffs