Iapitus The Impaler said:
Also, what are the soul king's abilities exactly? If they fall under Noble Phantasm or overlap with what a known noble Phantasm does, then Nega-Summon should be able to counter it
Rei-o means Soul King.
Now. After he willingly got sealed away. The 5 noble houses did this to his body.
From the light novel:
"Perhaps it was because he could see the far-flung future.... Maybe he could not escape his fear; or maybe he found some hope in the new world.... I don't really understand... But the Rei-o dared not resist it." The monk lowered his eyes and then repeated his first words.
"But the Tsunayashiro ancestor doubted even this non-resistance.
Afraid of the Rei-o escaping from his seal by himself; he neither wanted the Rei-o to live nor did he want to kill him. Continuing this helix of contradictions, the Right Arm of 'stagnation' and the Left Arm of 'Progress' were torn off."
The recruits drew in sharp breaths. The four members of the Zero Division, except for the monk, had unfathomable expressions on their faces; but they remained silent.
The monk then stated a cruel fact in a flat tone as if he was talking about the weather.
"Well; I suppose that still wasn't enough. The ancestors; including Tsunayashiro;
gouged out his heart and internal organs; and dismembered both his legs. Doing so, they destroyed his power; creating a king convenient for themselves."
Upon hearing the monk's tale; Shutara Senjumaru, who had remained silent until then, opened her mouth with a smile. But that smile was heavy with traces of insurrection.
"Convenient indeed. He continues to remain the lynchpin without ever having a say in the workings of this world, while the real business is carried out by others."
Governs Stagnation/Stillness with his left hand- Has resistance to Precognition as Rei-o is in a state of Stagnation. He has no past and no future.
Governs Progress with his right hand - Can adapt in the course of battle to his opponents and copy it's abilities, stats, and speed. Can self-multiply with a Hive mind. (Plus Soul Regenerationn.)
Governs Fate & Clairvoyance with his eyes - Can see all possible futures from the present into the far future and choose what event from the future becomes reality by bringing said event from a possible future to the present. (Works on souls, weapons, and the environment.)
Governs Hope with his heart - As long as foes have doubts in their hearts the masses turn in favor of Rei-o and he can turn any physical damage into God Size. Basically, Immortality + Evolutionary Power Reaction + Size Manipulation
Governs Imagination with his brain - Anything he imagines becomes reality.
Governs Desire with his nail - This one was originally's Matsumoto's fragment of the Rei-o that Aizen took from her and added to complete the Hogyoku. This was the piece of her soul that Gin wanted to get back from Aizen and kill him. It grants you any wish you have that is withing the possibilities of your own power. Aizen's monster form according to the data-book is the form of a Rei-o.
Governs Matter with his soul chain - Created the world of the living by splitting the old world made of reishi (spiritual matter) and created the world out of Kishi (Matter), and stated in the manga reishi and kishi don't mix well. That's how the worlds were separated.
Governs Life & Death with his bones - This is the most vague one of them all. Rei-o created Life and Death this concepts didn't exist in the old world. Now. Ichibei in the manga tells Ichigo that Rei-o gave him the Oken (Rei-o's bones), but in the light novels is explained further that Ichibei took the bones. And you guess it. Ichibei's power allows him to control life and death.
A quote from the light novel to describe his power in a nutshell:
"That's right. Others; with special powers, including myself; appeared, but it is fair to say that the Rei-o stood out; his powers very close to omnipotence and omniscience."
