When Danny is fifteen, Dani destabilises.
They did their best to save her.
Their best wasn't enough.
After the grief comes the realisation that Danny is immortal. Oh, he will surely die a second time, but his future as a ghost is pretty much assured.
He will have to bury many more of his loved ones, and very few will follow him to the afterlife.
Here is Danny's most well-kept secret: he knows what it takes to make a living being into a ghost at the moment of their death. He has never spoken a word of it to anyone, and he never will.
But it gives him the idea to ask his loved ones if they would follow him to his strange sort of afterlife in death.
(Well. Not all of his loved ones. He knows what his parents' answer would be.)
They've followed him to the Ghost Zone before, and they see nothing wrong with making a permanent residence there when the time comes. They won't leave him to face eternity alone.
It devastates him, but Danny accepts it.
He has to. His method only works on the willing. He doesn't want to think he would force this on anyone, but he is also glad the option isn't there.
They have decades to live together. Who cares if they don't have forever? His time with her will be no less precious for it.
Except they don't have decades together.
When Danny is on the cusp of his eighteenth birthday, he, his friends, his family and Vlad are caught up in the blast of an explosion. His world detonates around him and he survives it only because he was in Phantom form.
Danny buries his loved ones and the godfather he never wanted.
(Vlad had promised they were one and the same. That if anything, they would survive each other.
He was supposed to be the one that understood. The one that stayed.
Vlad was wrong, and Danny hates him for it.)
He goes after the GIW, who were responsible for the explosion, and makes them regret it. He doesn't go so far as to kill, he knows too well the price of death, but he makes sure they would find death preferable.
It takes a week for Sam and Tucker's ghosts to form. When it does, Danny disables the portal and leaves Amity Park behind. He takes his best friends with him.
They go to Gotham City, where their obsessions can more easily be fulfilled and the ambient ectoplasm is ideal for newly-formed ghosts.
Sam and Tucker are different now.
It is harder to rein in their impulses. Danny does his best to remind them to be careful around humans.
He buys the three of them a mansion with Vlad's money. It's properly goth and outfitted with the latest technology. It's decently isolated so they don't have to pretend to be human out there.
His best friends are different.
But he marked them for death before tragedy happened and it had the unforeseen side effect of letting them retain more of their identity than any ghost he has previously encountered.
They bicker as much as ever.
Sam nags him into attending his classes at university, Tucker forces him to make living friends.
When he meets Tim Drake-Wayne and falls in love, they cheer him on.
If he wasn't already half-gone, that boy would be the death of him.
He makes Danny believe life is beautiful again.
But Tim is accident-prone. Every few weeks, he has some sort of injury. Sometimes they are extreme sports-related, sometimes they have to do with the infrequent kidnappings he and his family are subjected to.
Sometimes he is collateral in a rogue attack during one of his family galas.
(Why anyone still organises galas in Gotham is kind of beyond him.)
Sam and Tucker think Tim is hiding something, but they respect Danny's desire to wait and see. He has things to hide too, after all.
But he is starting to want forever with Tim and he does not know if he wants to wait until they trust each other to find out if that is something he can hope for.
So he asks him one quiet evening, where their hands are interlinked and their eyes fixed on the stars in the planetarium Tim bought them tickets to.
"Would you want to live forever if it meant you were no longer human?"
(Tim thinks about Ra's Al Ghul, who has lived centuries and become so twisted he cannot rightly be called human.)
It hurts, but it is his choice. Danny accepts it.
A day later, he breaks up with him.
Better to save his cracked heart from further shattering.
Tucker philosophises, sitting on Danny's bed. He's been rotting in there for the past few days, skipping class to mope around instead.
"It's like asking your partner if they want kids one day but for half-ghosts, I guess. It's better to know immortality's a dealbreaker now than after you're married."
Sam nods, her glowing purple eyes soft with sympathy. She is floating on top of him, the tip of her combat boot intangibly passing through his elbow.
"You'll find your happily ever after, Danny. I'm sorry, I know you really liked him."
"I loved him," he mumbles, burrowing further into his sheets.
"And I'm sure he loved you too. Unfortunately, sometimes love isn't enough. You have the right to save your heart for someone you won't have to grieve. You've lost enough, Danny."
"Maybe I don't have to grieve him, but I'm losing him anyway. It feels less like self-preservation and more like cowardice."
But he's made his choice, and now he has to live with it.