Who is the fastest comic book character?

That's an easy answer; The Silver Surfer There are other characters that are faster, like for example his own creator Galactus, among other cosmic entities but see they're not "heroes" they're neutral, neither good nor evil. Surfer is much faster than even the likes of the Flash or Green lantern of the D.C. universe because, he can travel through time, effortlessly. Hunting down planets when he was Galactus' herald, call it a "job requirement," required him to be able to "transcend time and space." The entire universe is his playground; no part of the universe is inaccessible to the Surfer, its the same with all of Galactus' heralds.