Demon Twins AU
AKA "Danyal al-Ghul is seven minutes younger than Damian. Those seven minutes mean something."
Danny loved his older brother. Even when Talia favored Damian over him, even when Ra's spared no expense for his brother's care, even when Danny was left unprotected against their mentors' brutality without the title of heir. He swallowed the bitterness of jealousy and instead accepted any affection Damian could secretly give him away from Ra's prying eyes.
He knows Damian loved him, too. As much as Ra's and their mother allowed, as much as being in the league allowed. It was the hitch in Damian's breath when Danny was hit a little harder than usual, bread under his pillow when Danny was sent away without food, the twitch of his lips when Danny said an amusing joke. They could never hug, never speak openly, but Damian always had a small, secret space in his heart for his brother. (Danny and Damian learned early on to never show affection. Danny was once gifted a hawk for his birthday, only for Ra's to slaughter it once Danny had grown to love it. He had nightmares for months that Damian was forced to slaughter him. He woke up every morning feeling sick because he couldn't remember if he'd forgiven Damian in his dreams.)
The only thing that tested Danny's love for Damian was when he left. His mother didn't tell him that Damian was gone. He'd carefully crept into Damian bedroom one night, asking if he'd go stargazing with Danny, when he realized Damian was gone. All his clothes, weapons, gone. There was a single bare mattress. It wasn't until weeks after that Danny's mother told him Damian was sent on a mission as the heir to train with the notorious Dark Knight of Gotham, their father.
There was that bitterness but this time, Danny couldn't swallow it. The emotion sat in his throat like acid, burning in his eyes and throat until he could escape to his bedroom that night. Muffled a scream into his pillow and felt sick, agonizing fury. Jealousy, grief, resentment. It didn't subside for weeks, months, until aching loss of Damian's presence replaced it.
And then Danny's first and only mission.
Kill the heir. Murder his own brother. Danny's grandfather had always looked at him with contempt, hatred. But there was something truly terrifying in his voice when he'd gripped the back of Danny's neck, growled do not disappoint me, and released him into his mother's waiting arms. "He was softened by your father. Dulled and weakened. Don't forget, Danyal," Talia said to him. "The more you care for something, the more sway it has over you. The more it ruins you."
Danny hadn't believed her.
Even as he boarded the private plane, Danny wondered if he could join in Damian's life: fantasies of living in an apartment, stargazing, learning who his father is. Finally learning if Damian had started drawing like his hands always yearned to. Wondering he could see the stars in Gotham as well as in the desert. Danny was almost too eager to see his older brother again, practically giddy at the thought of a reunion away from Ra's and their mother.
Except Damian's hair is... longer. Two older boys are on either side of him and one reaches over to ruffle his hair. And Damian turns with a wide, unguarded smile that Danny's never seen. Watches as one of the other boys hands Damian a takeaway cup of coffee and Damian drinks it without any hesitation. Watches as they banter back and forth, Damian's shoulders no longer rigid with immaculate posture or tense with hypervigilance. Danny watches as Damian acts as if he... as if Danny never existed, as if he'd completely forgotten about him.
The all-consuming ache of Damian's absence is crippling. Worse still is the anger, the rage of being left behind and forgotten while he suffered. Danny was forgotten despite how many times he forgave, loved, hurt. This stranger stands in Damian's place.
(And maybe Danny's mother was right. Danny's never loved anything more than Damian, yet mere moments of watching his brother interact with his new family makes him feel... ruined. A forgotten memory to be tucked under Damian's bed like blunted pencils hidden from their grandfather.)
It... doesn't matter. Danyal al-Ghul has a mission to complete.
