User blog comment:Xilinoc/Ch. 616 - Mimihagi-sama/@comment-2146692-20150219123126/@comment-5398287-20150219124716

Well, assuming that there are 3 other gods in the outskirts of Rukongai, each representing another one of the Soul King's missing limbs (his left arm, his right leg, and his left leg)...

The Soul King is Exodia, the Forbidden One.