We already have Hercules, Hades and Megara to come, so who else may join them? Will the second half of this season of ABC's Once Upon a Time introduce the whole world of Hercules? 'Once Upon a Time' Showrunners Talk 'Regina the Savior' Story Arc Once Upon a Time fans already know that they will be meeting Hercules, Megara and Hades, played by Jonathan Whitesell, Kacey Rohl and Greg Germann, respectively.