They using healing magic to help keep themselves healthy. (dragon-quest.org)
The bosses are stronger than these basic enemies, but tactically I found it most effective to just set my team to support me before battle with healing magic, while I repeated the same 3 hit combo with the occasional special move or grenade toss till the boss eventually died. (thebuttonsmashers.com)
Said removal is no joke either, as opposing heroes are given absurdly high vitality and healing spells even if the character can never learn healing magic when you play as them! (hardcoregaming101.net)