Volthoom has been retconned into the force that originally spawned the infinite DC multiverse(including higher-dimensions, like the New Gods' realm and whatnot.)
Godhead #1 established that Volthoom became the proverbial 'Hand of Creation', which spawned the original multiverse(along with it's higher-dimensional spheres/realms): (please log in to view the image)
*Note that the Hand is wearing a GL ring on its right middle finger.
Here is a more thorough breakdown...
Volthoom was first shown in this capacity right after the Guardians originally witnessed the 'Hand of Creation' whilst peering back into the dawn of time... But upon closer inspection, they noticed that it was wearing a GL ring: (please log in to view the image)
*Note the GL ring on the middle finger of a right hand.
In a nutshell: the Guardians witnessed this Hand birthing creation, noted that is was wearing a GL ring, their instrumentation inextricably shattered, and *poof* Volthoom(in his original/human form) arrived. He then taught the Guardians of the emotional spectrum and convinced them to purge ALL of their emotions -- thereby creating the First Lantern/Ring(and empowering himself) by proxy: http://i.imgur.com/0w07Crs.jpg
We later learned that peak Volthoom had harnessed the power of the emotional spectrum with the intent of "unwinding the fabric of history" for his own purposes: (please log in to view the image)
Volthoom then literally pulled the first(and barnone most powerful) GL ring from inside of Ganthet: (please log in to view the image)
*Note that he places the ring on the middle finger of his right hand.
This panel makes it clearer to see the ring's placement: (please log in to view the image)
*Again: Middle finger. Right hand.
Why is this important? Because when Volthoom used Hal as a focal point to gain access to the dawn of time, he began unraveling ALL history, starting at the beginning... He became the Hand of Creation: (please log in to view the image)
*Note the GL ring on the middle finger of his right hand.
How do I know Volthoom was *actually* collapsing/altering the entire timestream? Because WL Kyle could literally feel it happening: (please log in to view the image)
And as mentioned above, Volthoom's hand was featured again in Godhead #1, and described as the force that originally spawned the entire multiverse, as well as the Old(and New) Gods: http://i.imgur.com/OvgYg3k.jpg http://i.imgur.com/cQGHFHq.jpg
*Note a ring on the middle finger of a right hand.
It's also worth noting that Volthoom(esp. 'peak' Volthoom) is completely unkillable -- even to an entity such as Nekron, who is the abstract embodiment of death/oblivion: https://i.imgur.com/kVC3ELl.jpg https://i.imgur.com/kcIDcM4.jpg
Nekron: "You are beyond my reach, human [...] Already the emotional spectrum is pulling you back to the realm of the living."
And even the Guardians believe that death at the hands of Nekron represents the most permanent type of death one can endure: https://i.imgur.com/55O6IWU.jpg
Rami: "You were killed by Nekron. That's as dead as it gets."
*I'm sure that stems from Nekron's classic depiction as "Death as a cosmic certainty... Death as the ultimate opponent": https://i.imgur.com/zvLrqZQ.jpg