You suicide your team apart from 1-2 chars, place them in a way that Meno produces 2 glyphs such that the crystals will only leave a diagonal opening to these characters. The mobs will run away foolishly. 5 turns later the crystals will disappear, but you can repeat the same thing despite taking a bit of damage inbetween. Emerald, Dokoko and/or Watcher's Dofus on both chars and you won't even need heal. Sooner or later you'll finish Meno with the %dmg buffs. It's "auto-win".
Just look up duo or solo