User blog comment:Xilinoc/Ch. 621 - THE DARK CURTAIN/@comment-5551986-20150326174555

Probably had to restrain the soul king for his own benefit. Maybe he gains power from each soul similarly to Yhwach. And obviously the population gets larger so with each reincarnation and death some power goes to him. Perhaps they restrained his power due to him becoming increasingly more powerful, unable to control it, hence the reason for his missing limbs, sealing into the vase, and change of address to several hundred miles in the sky, or something. Take Aizen, yeah hes powerful, people and objects of insufficient power like explode being near him or disappear, maybe the weaker souls in soul society get damaged and die needlessly or worse so for the benefit of the stabilization of the realm he chose to have his power sealed by his own underlings the shinigami and make himself weaker so as to not disturb regular souls.

Its been hinted that powerful beings shouldn't use their powers all willy nilly. Captain level people seal their power in the human world, Ichigo might not be able to return due to his power, Aizen blows people up when they go near him. Perhaps the soul king after millennia of gathering small amounts of power is just like a super station of power.

This stupid theory makes sense to me, it all relates to balance. Hell, if the soul king created other arms and stuff and even Yhwach whos not to say that they are all split powers he once possessed, seems like Yhwach never had a proper mother, or rather a spirit queen one. So either he is a phsyical creation of imagination or the soul king pulled a Yahweh and impregnated some random woman called Mary. The shinigami are helping the soul king, but probably attacking them now because Yhwach took the soul kings power and instructed them to attack?

Either that or the Soul King was just some monster and the shinigami felt like keeping him prisoner. BUT, people say his true nature may not be benevolent (in my opinion he is neither benevolent nor malevolent) he probably just mediates everything and just "is" hes a force of nature and a reason for the existence of the world of their time, he might not even have any ideals or thoughts, he is just something that reacts to other stimuli to keep the world going similarly to the four fundamental forces of nature, strong interaction, weak interaction, electromagnetism and gravity. He represents all four in one (grand unification theory) and ensures the world functions.

Besides, the way the Royal Guard speak of him, hes doesn't seem to be some monster, he seems like an ok guy apparently. The zero division seem pretty loyal and speak highly of him.