I think you should fix the recommendation in the guide, it told you to buy 5 dark orbs to level up 1st before this fight but even with ??? & MC at level 6, they still dealt piss poor damage against the fairy boss (they're definitely more tanky & that's a good thing, but their damage is so low). Not to mention she can summon a healer plant minion to heal herself every turns.Hmm? Did you bring a dead girl with you? It would be much easier if she were in your party.
Speaking of ???, can we rename her in the future or at least find out what her name is before she died?