Make an MP tank weapon for Maria and/or give her and Sophia Convert Damage to MP (Preserve HP - Tattered Tome) and MP Regens.
If your two don't have that then that's why they keep dying. Their HP and DEF isn't worth squat ;p
Other than increasing their durability through converting damage to MP if you don't want to do that then try sticking to long range mode as much as possible and not getting hit ;p
Good luck lew
SuperJolt -
Awesme! Have fun with your current game
Yeah I love high MP bars too - only thing was once when I got Peppita to 50'000+ MP when I had the Valkyrie Garb equipped and fed her all the HP plus berries as well she had 99'999 HP along with it
