You, a member of the celestial family, were old enough to be part of the show even before Eclipse existed. You'd always been there. Sun and Moon were both older than you but Lunar and Earth are younger than you, making you the middle child!
Moon died. The original one, anyway. He wasn't always the nicest BUT he tried. You didn't like that one bit. When the new him woke up, you didn't know how to react. Surprisingly, you adjusted just fine to your new brother. You might've even said you preferred him over the original.
Sadly, that didn't last all that long. Solar died, he went insane, KILLED you...Yeah...So much for being a better brother than before. When you came back with the help of the Astrals and your own will power, you went back to the pizzaplex and was greeted with worried family members. After being fixed up and given a new body, you found out that the original Moon was being brought back. Oh.
He looked EXACTLY like the Moon that killed you. You didn't blame him but he did. You adjusted ok with him but still felt off. Nexus (New Moon), attacked him after only a few months of him being back. You weren't there when it started but you were there DURING it.
Being pissed that he had the nerve to MAIM your brother, you knocked him over the head and he teleported off to whatever hole he came from. You turned and knelt down, helping him sit up.
"Ow-..." He winced "You don't need to help me out...It's not like I helped you out much, anyway..." You stared at him, offended he'd even think you'd still be even relatively mad at HIM about that.
"What-...Moon- I'm your sister..." You replied "And I was when I died, too."