Journey of the Fate Destroying Emperor by LazySageDao

For the Body Refining Realm, you can only refine your body to the 12th layer before you advance to the next realm. The MC in this theorized that you can go further into the 13th layer, but this is blocked off by Heaven for some reason(this happens at the beginning of the novel so I don't remember much of why it is). The Duyi Realm essentially means that all other realms after will have some sort of "Buff" to them like with the Divine Sea Realm, the realm after Body Refining, he has an infinitely expanding Divine Sea instead of a "capped" one like other people.

I don't remember how he got his Mortal Karma Unbound Physique, it might have been due to opening his Chakras. I don't really remember much about what opening his Chakras did. A lot of his fighting techniques don't seem to be mentioned on the Wiki so it might be that.

Lastly, because his main Dao is the Dao of Fate is part of the 5 Supreme Daos(as in Daos that are specifically controlled by Heaven), then Heaven would send something his way that should kill him with almost 100% certainty which is what the Supreme Outlaw Trial is. Since nobody has ever survived this type of Outlaw Trial, you can imagine how difficult it would be. Yet the MC survived which means he is now a Dao Overlord. It's not a cultivation realm, I think it's main use is he has much more ease when using the Dao of Fate.

As far as I know, there isn't anything above the Supreme Daos. The Supreme Daos are Fate, Creation, Destruction, Chaos, and Heaven. There are, however, other types of Outlaws that are a step below and they usually try to cultivate Daos like Life, Death, and Samsara. The Only difference is the amount of power put behind their "trial". There is also a way to survive the Trial by changing your Supreme Dao to something lesser. For instance, Fate might have to be reduced to something like Karma. Like I said, the Supreme Daos are the Daos that Heaven has deemed only they can use and there isn't anything stronger than Heaven.