I wanna know about Aster :)))
So you'll hear about him mostly in backstories because He's kinda an abandoned character but
He's a Gaster from my first au! And because all other Undermine Multiverse AUs come from it, he exists in those too
In the original one, He's the royal scientist and a father of Lun and Sol, He's immortal(ish) and was the King of the Underground in the first few years after the Skeletons were trapped there
Since He's a father of Lun and Sol, he is also technically a father of any Alternative version of those two
So Eclipse and Solar, Moon and Sunspot, Starling and Canary, Nebula and his unnamed brother, Twilight and Sunrise, and Mahina and his unnamed brother
Aster is mostly dead or missing in those Alternative versions
But besides that, He's a good father and he's divorced because his wife, Valeri, is transphobic and she sucks
Hope this makes sense?