What Am I? - A Riddle -Part Two-
I flow by everything on earth and space,
No one can oppose me, even if they brace.
I make people die, to leave only bone,
I gnaw every metal, and crumble any stone.
Though I sound unpleasant, you must need me,
To live everyday, and to walk free.
I might ruin all, but I also change all,
Without me, we will have no fall.
Once I have passed, there is no turning back,
For those who lack, the future may be black.
I rarely stop by, I almost never do,
With all these clues, you may know who.