system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] Who are some insanely powerful "human characters"?

The reference I'm using is Franklin Richards or Legion form Marvel. Characters that could create/destroy galaxies and universes but could hide in a crowd without having to shape shift or hide their appearance.
gpt
Alexander Luthor Jr of Earth-3 was, under a very specific set of circumstances, a Franklin Richards level threat. Those Circumstances (Infinite Crisis) are now long passed and Alexander long dead at the hands of the Joker.
 
The next closest existential threat in human form is likely the Flash. It can be assumed that the Scarlet Speedster of Central City, and probably this new Crimson Comet in Keystone,  is capable of altering time in drastic and largely unpredictable ways.