I died, and behold I am alive forevermore, and I have the keys of Death and Hades (Rev 1:18).
There's probably a connotation to this verse that's lost on modern readers. We think of "death" as an abstract term for the cessation of life. The physical condition of the decedent. A corpse–which undergoes rapid disintegration. And that's it.
However, for ancient readers, I suspect "death" would have an added connotation. In ancient polytheism, you have gods of death, viz. Osiris, Hades, Pluto, Dis Pater, Thanatos. In part, these personify the end of life. The notion of death as a personal agent who takes life.
But in addition, gods of death ruled the netherworld. In pagan folklore and mythology, when you died, that wasn't necessarily the end. Rather (depending on the tradition), your soul descends to the underworld. There the god of death rules over you, for the duration. When you die, you transition from the domain of one god or gods to the domain of another god. You are now under the thrall of the king of the the underworld. Death is your god. And a very dismal god at that.
On that view, Rev 1:18 demythologizes the gods of death. Imagine how liberating that message would be to gentile Christians raised in paganism. There is no god of death who controls the afterlife. Rather, there is only one God for everything. Your postmortem fate is in the hands of Jesus.
I'd add that paganism is not a dead religion (pardon the pun). It's entrenched in parts of the third world and the indigenous folk religion. Moreover, immigrants from those traditions bring it with them. From a modern missionary standpoint, as well as evangelizing immigrants, this message can be as liberating as it was in the 1C.