It had been six hundred years since Danny Fenton first faked his death when he realized he wasn't ageing. He looked to be in his early twenties, but people who first meet him swear that his eyes are much older than that. When he isn't focused on a task they stare ahead, dim in the light and that his mind is a million light years away.
Then he blinks, and he's back. He does his task dutifully and perfectly, slowly climbs the ranks in the Galaxy Garrison to a teaching assistant, and catches three of his favorite students on the roof one night, looking for aliens.
He goes along with them when the alien ship crashed into the desert because fuck, he's been looking for aliens for six hundred motherfucking years and he ain't gonna follow commands when he was so close. Pidge is able to hack quickly into the cameras and he feels a surge of pride for them.
When Lance and the kid that Lance called "Keith" had run out of the pop-up tent with his old instructor Shiro in their arms, he instantly knows that he won't be coming back to the Garrison for a while. Stealing a technical prisoner from the government tends to get you recognized for a few years.
Shiro recognizes him when he wakes up the next day, and Keith talks about the ruins inside the cave systems. Danny remembers that this place used to be uninhabited for years back before he died, that it's logical that ruins seemingly made by aliens wouldn't have been discovered for a while.
When they find the lion Danny feels a surge of energy, energy that hasn't touched humans before.
Lance can't fly in simulators, but in this lion he doesn't fly. It's like the ship is a part of him as he dodges the lasers from an alien warship (Aliens! Aliens are real!) and he feels so damn proud of this kid. He's flying a ship that was made for aliens and doing it perfectly.
When they go through the portal that feels like its unstable, he panics a little and may have pooled a little bit of ectoplasm into his hands, ready to surround these kids in a shield if this was a trap, but then they reach the end and a beautiful planet is in their sights, complete with a beautiful castle.
He waved off the kid's pesters of "what the fuck was that green shit mr fenton'' and shiro's "danny what the fuck" saying he'll explain it later.
When he starts floating, which seems more natural in this ever so slightly heavier gravity, he laughs at the shriek from the other kids and smiles. "Not now, let's go explore this alien castle!"
They all think he's a bit too excited. They follow him anyway. Whatever Danny is, they'll rather have him in front of them so he could protect them. This was Danny who gave the students contraband candy and wears pink socks under his crisp uniform, who Shiro had to give a detention to once because he beat up someone who was badmouthing ghosts.
Ghosts. Shiro's eyes widen as they walk down the steps of the alien castle.
Danny was a ghost.
When Allura and Coran fell out of their pods, it was Danny who assured them that they were alright and explained what was going on easily. And explained to everyone what he was.
A half ghost. Pidge excitedly went into several technical terms and Hunk followed shortly after, grabbing his hands and admiring the structure and being way more interested in a ghost then the aliens that were rather confused and puzzled until Danny started floating again.
He didn't get a lion, but he didn't take it personally. His powers, aging in his human body like wine for six hundred years, were more than powerful enough to almost match the lions. He could help in his own way.
He finds some spare paladin armor and it changes when he finally transforms, the metal tingling with new ectoplasm and a new technology.
His eyes were not dull anymore. He had a new purpose in his long life and he was going to do his damn best to save the universe.