Seriously...Why the clarification?

God

Zoom?

The phrase flows better than fastest man ever

The Black Flash. He's the Death version of The Flash.

I read: "why is flash called the fastest man alive when there is an even faster but dead dude" ....I faceplamed.....

Because it sound better than 'the fastest man'

The reverse flash...he's technically dead.

... that means fastest man now, but not ever.. so kinda yes, they are not excluding the possibility that a dead man was faster, but like, when he was alive.

I have no regrets of saying this but, quick silver

The Black Racer. The literal embodiment of death for all speedsters.