We have no ED 'familiars'.
We have ED tattoos. ;)
Why don't we have an EO tattoo? Because EO's are boring/basic/whatever you want to call them.
They do thier stuff pre battle, and can't be manipulated (apart from your own DM).
How could we make an EO tattoo that's more interesting than;
Tattoo of MOAR EC: Equip this Tattoo to gain MOAR EC!!
Seems about the right time to ask for folk to throw out ideas for making an interesting EO tattoo!