Classification: Non-corporeal extraterrestrial race 

Location/Base of Operations: Unreveraled;
     they are pparently extinct with the exception of Stardust, who is mobile throughout the universe

Known Members: Stardust (Lambda-Zero);
    Hadria, J/Psi, Tau (these and all others are apparently deceased)

Affiliations: None known

Enemies: Annihilation Wave, (indirectly) Annihilus, Galactus (Galan), Stardust

Powers/Abilities: The Ethereals are composed of short-lived particles, like quarks and leptons, and they seem to be beings of energy rather than matter. 

    As a result, their appearance and natures are ever-changing. 

    They can form a strangepac (as seen in the top left image), a protective grouping, to escape forces that might otherwise destroy them. 

    At least some of the Ethereals can project energy blasts. Regardless, even a group of over 50 of them was no match for the Power Cosmic-enhanced Stardust.

Traits: Due to the short-lived nature, hey exist in an ever-changing reality, and they build short-lived monuments from radio waves and works of art out of quarks, which break down in picoseconds into dull, inert matter.

    Ethereals fear death, but they do not truly believe in it.
     They believe in only four things, the fundamental forces:
          (1) The strong force, which bound the quarks and leptons into atoms;
          (2) the electromagnetic force, which shaped the atoms into matter;
          (3) gravity, which pulled them all together;
          (4) the weak force (van der Waals forces), which made them burn. 

Type: Energy beings
Eyes: None
Fingers: None
Toes: None
Skin color: Ethereals do not have skin, but their energy forms vary among various colors, presumably including various shades of red, orange, yellow, green, blue, indigo, and violet, as well as ultra-violet, infra-red, and various other forms invisible to the human eye
Average height: Variable
Note: Stardust is apparently unique in deriving a corporeal form

.

.

.

     They built giant monuments from radio waves, created works of art, out of quarks, which broke down in picoseconds into dull, inert matter.

    Their culture and their people were one: Constantly mutating, each particle evolving instant by instant into challenging new forms. 

.

(Annihilation: Heralds of Galactus#1/2 (fb)) - An unrevealed time period ago, the being Lamda-Zero was born into this stimulating, ever-changing Ethereal world.

     Lamba-Zero hated that existence. 

(Annihilation: Heralds of Galactus#1/2 (fb) - BTS) - Lambda-Zero knew the Ethereals Hadria, J/Psi, and Tau.

.

(Stormbreaker: The Saga of Beta Ray Bill#1 (fb) - BTS) - Adopting the identity of Stardust, Lamba-Zero became the herald of Galactus, her power greatly enhanced by the Power Cosmic.

(Annihilation: Heralds of Galactus#1/2 (fb) - BTS) - Either before or after Stardust's destruction, the Annihilation Wave assaulted the world of the Ethereals, raging through their cities and destroying their entire civilization at the heart of their sun.

    Only fifty-three of the Ethereals (including Hadria, J/Psi, and Tau) narrowly formed a strangepac in time to escape, while the rest of the Ethereals were reduced to their component particles, to cosmic ash. 

    This strangepac ventured into the void of space seeking Lambda-Zero.

(Annihilation: Heralds of Galactus#1/2) - Stardust reformed himself and was drawn to the Andromeda Galaxy by the Power Cosmic. 

    The Ethereals' strangepac confronted Stardust as she flew through space at faster-than-light speed, demanding, in the name of the four forces, that Stardust explain herself and answer for her crimes. 

     Making no apologies and considering her reasons no concern of their, Stardust suggested that they leave her to her path and instead return home. 

    After the Ethereals noted the circumstances by which they had no home, they further accused Lambda-Zero of being off fighting the corporeals' war rather than helping her own people. 

     Not denying this, Stardust countered that the corporeals were superior beings, performing great deeds and building magestic structures that lasted for thousands of years. 

(Annihilation: Heralds of Galactus#1/2 - BTS) - Stardust then returned to Galactus, who noted that he had reclaimed the Silver Surfer as his herald and that Stardust had been an inconstant servant...too changeable, too subject to the blowing of the cosmic winds...too ethereal. 

.

     When Galactus asked her to prove her worth and loyalty, Stardust initially considered that it would be too monstrous to surrender the Ethereals' energies to Galactus,and the Ethereals sensed this and screamed out within Stardust, aware of what she was considering. 

(Annihilation: Heralds of Galactus#1/2) - Ultimately, Stardust chose loyalty to Galactus, and she fed the Ethereals to Galactus.

.

(Annihilation: Heralds of Galactus#1/2 - BTS) - While the energies of this small group of beings was barely a morsel to Galactus, he was impressed that Stardust had willingly delivered to him the last survivors of his own race.  Galactus then resolved to accept having two heralds at once.

 .

  Stardust ultimately considered that the reason for her actions was that she loved Galactus.