These are all my headcannons, tho you can add what you think their actual second gender should be in a moment
Sun: alpha (being the biggest celestial body in the solar system, having a bright shining color, and a loud booming voice that can be heard all over the solar system, I think he would be an alpha, and he rules over all of them as if being the highest in hierarchy)
Mercury: omega (not just because hes the smallest, but because he [used] to be shy and not much of a backtalker, and got hurt easily, and his temperatures are both hot and cold, like omegas heats [possibly?])
Venus: beta (although he can be snappy, rude, and often punches before asking questions, he can be shown feeling sorry and feeling bad about about himself and willingly admitting it)
Earth: beta (he is still slightly selfish even after the revolution, but he's getting better, acting more calm and kindhearted, but still teases the other rocky planets, and can be a little bit of a 'meanie' when laughing when his friends get hurt, but anyway he acts like a beta)
Mars: beta (be honest, he's got all the beta characteristics, he's calm and tries to stop fights, only gets involved if needed, and comforts others and plays games such as uno calmly and doesn't get frustrated too much)
Jupiter: alpha (the rocky planets called him a failed star, so they may see him slightly like Sun who's an alpha, he's the biggest planet, and often shushes Saturn and protects him like an alpha would for their mate)
Saturn: omega (he's called beautiful, like omegas may often be, and hes very sensitive and mostly to sadness, he cries a lot and gets overly worried when someone he deeply cares about disappears for just a moment, like a omega and their pups)
Uranus: omega (he's like an omega who doesn't want a mate, being introverted and independent but still want in praise and getting nervous when around others bigger than him, and having a diary that he doesnt want anyone to see, like he hides his crushes in there)
Neptune: beta (he's energetic and funny, but oblivious and annoying, but no one bothers to really 'punish' him because hes not an omega that they can just claim, and he's often getting the plot going like he's more important than a omega like in most ABO au's)
What do you think their secondary genders should be?
Sun: omega, beta, or alpha?
Mercury: omega, beta, or alpha?
Venus: omega, beta, or alpha?
Earth: omega, beta, or alpha?
Mars: omega, beta, or alpha?
Jupiter: omega, beta, or alpha?
Saturn: omega, beta, or alpha?
Uranus: omega, beta, or alpha?
Neptune: omega, beta, or alpha?
Extras with no reasons:
Pluto: beta
Charon: omega
Ceres: beta
Eris: alpha
Makemake: beta
Triton: beta
Haumea: omega
Titan: beta
Ganymede: alpha
Europa: alpha
Io: omega
Callisto: beta
Titania: beta
Luna: beta
YOU ARE READING
Solarballs/planethumans Omegaverse
Fanfiction(NOT MY ART ON COVER!!) Just an idea on who would have what secondary gender and traits and outfits and stuff if it was ABO universe, all these are my headcannons and may have ships you dont like, not cannon
