Heralds of Galactus

The Heralds of Galactus are beings empowered by Galactus to seek out worlds to feed his hunger. The first known Herald was the Silver Surfer, who swore to serve Galactus to save his homeworld of Zenn-La. After the Surfer parted ways with Galactus, he took on numerous replacements in subsequent years: Air-Walker, Firelord, the Destroyer, Terrax, Nova, Morg, and, most recently, Red Shift.

The Heralds of Galactus are ultimately subject to Galactus' will- he can revoke the Power Cosmic granted to them at will, and alter their minds as he sees fit.

Alternate Timelines

In one alternate timeline, Dazzler became a Herald of Galactus after Terrax. On Earth-952, where the Surfer remained with Galactus (who did drain the Earth), the Fantastic Four eventually replaced the Surfer, becoming his Heralds and consciences.

Comments

Considering the number of Heralds Galactus has had since the Surfer, it seems likely Galactus had them before the Silver Surfer as well. Superman was briefly a Herald (between Morg and Red Shift) in Superman/Fantastic Four.