People think Superman is the Justice League's most powerful member, but it's actually the Flash.
The Justice League's strength rankings change, but a Kryptonian's perspective says the Flash is the most powerful. Barry Allen's progress and compassion win him this level, not only his might and ability.
In Adventures of Superman: Jon Kent #6, Tom Taylor, Clayton Henry, Jordie Bellaire, and Wes Abbott, Jon Kent, stranded in the Injustice realm, prepares to fight Injustice Superman to free Batman and Harley Quinn.
Jon must kill the rest of the world's Justice League, "with the most dangerous first," to reach Superman. He seeks out Barry Allen to calm him in a chat that seems to last hours but lasts only a few minutes.
Barry Allen's powers make him one of the multiverse's greatest threats. Jon Kent outruns Wonder Woman in this issue, but The Flash is faster. Barry's speed allows him to distort the multiverse and travel through time, as in 2011's Flashpoint.
Since The Flash #800, the Flash can instantly switch realities. However, the Flash's compassion and powers make him powerful.
Jon tells Barry that "he's not a bad man...he's trying not to abandon a friend who has made some terrible mistakes." The Flash is the Justice League's most powerful member because of his unwavering faith in a friend and his ability to alter reality.
He can run across planets in an instant, but he still talks to a wounded friend. Jon Kent sees the Flash as Injustice Superman's most dangerous League member since he knows the Flash will do everything to help a friend and has the power to do so.
After their fight, Injustice Flash warns Jon, "If you hurt Clark, I will catch up with you." Jon confirms this as he flies off, knowing that Barry can carry out that threat.
The Flash is the Justice League's most powerful member since he can cross any dimension to save a buddy, even if it means breaking reality barriers.