Stephen Davis. Because that is the man responsible for what is essentially now an all toy-tie-in MLP:FiM universe. That was always intended to be though so, why should we care you ask? Because, this man loves being seen as Hasbro's sole savior and why it was put on the map again, globally.
If you want to be more informed, you can visit the link before and see why I'm pretty indifferent but disappointed in how rushed the MLP series has become.