How can a fairy take down a ten foot tall ogre? Is that even possible? I don't think so. Maybe with four? That is still hard to imagine.
What if each fairy adds more health to the other fairies? Let's also have the fighters add some ATK to the others, and spell casters add to the MAT. Each specialized fairy adds a little something to the whole group.
Four, why have only four? Let's get seven of them for an ogre. That would make a Swarm. What if we put eight of them... Whoa, that's a spoiler. Using Ellye's Combat Interface to get the additional fairies in battle. Using Swarm Effect: http://www.rpgmakervxace.net/topic/28008-how-to-create-a-swarm-effect/#entry195210
There is another developing part of the Swarm Effect. When there are more than four fairies, in the party, the main character's class is effected.