Gil-Galad somehow gets a Silmaril several years after kidnap fam is formed. He offers it in exchange for the twins.
"What do you want, Ereinion?" Maedhros demanded as he and Maglor sat next to each other in their main hall, seated on twin thrones. The Peredhil were somewhere nearby, watching from behind Maglor, most likely. Gil-Galad and his heralds faced them with clear animosity.
"We want our kin back." Gil-Galad said. "We are wish to trade for Elrond and Elros Eärendillion." Something cold pierced Maedhros' chest.
"You do not have what we seek." He said, shoving it away. He couldn't afford to feel in front of these Elves. Gil-Galad smiled.
"We do." He said, and held up a wrapped parcel. He teased a piece of cloth aside, letting the light of the Trees spill forth. Maedhros tensed, half his mind screaming to back away while his Oath forced him forward. He shoved both sides of himself down, out, away so that he could think rationally.
"You would give it to us freely?" Maedhros gritted out. You fool. Why would you bring that here? I will kill you for it, you know I will! He slammed his shoulders back, straightening so that, even seated, he made an imposing figure.
"If you hand over the twins, yes." Gil-Galad said. Maedhros decided he had never hated someone more in his life. Maglor keened, sorrow piercing every heart. Twin gasps came from the children perched on Maglor's lap.
"Don't send us away, Atto, Atya!" Elros gasped. Elrond let out a sob.
"The Oath." Elrond whimpered, his horrified realization washing over the bond. The pain made Maedhros grimace. He never wanted to hurt his sons.
"Do you accept, kinslayers?" Gil-Galad demanded. "The children for a Silmaril?" Maedhros hissed, hating himself. He'd done this to himself, of course. He'd sworn the cursed Oath and, just like the Valar had said, the Oath had caused them no end of pain. It was taking their children from them!
"How do we know this isn't a trick?" He demanded, biting his tongue to keep from accepting. "No one gives a Silmaril freely." The Oath snarled inside him, more pain wringing from him as it compelled him to just accept the offer.
"It is not given freely. We value children more than we do a Silmaril." Gil-Galad said sternly. Maedhros wanted to scream. He valued the twins much more than the cursed rock. How could he not? They were the guiding stars of his life. They'd pulled him back from madness. He loved them and couldn't bear the thought of losing them. He couldn't say yes. He physically could not say no.
"Atya, please." Elrond cried. His eyes were huge. Terrified.
"Elrond, no." Elros whispered. "Don't make it harder for them." He straightened and stepped forward, setting his face bravely as he regarded Maedhros.
"If it will satisfy your oath, Atya, Elrond and I will go with them. We don't want you to be sent to the Void."
"Yeah!" Elrond declared, tears still running down his face. "Take the Silmaril. We'll escape and come back. We're very good at escaping." He sniffled and put on a brave face like his brother. The sacrifice burned at Maedhros. He let out a snarl, standing and stalking towards Gil-Galad.
"If I hear a whisper of you mistreating them, I will kill you in your sleep." He threatened, grabbing the other Elf by the collar of his tunic. "Even if it sends me back to the Void. You harm one hair on their heads, and you will not see the morning." He snatched the Silmaril out of Gil-Galad's hand, the horrible force of the Oath finally fading. Then it broke, with a snap. The Oath was gone. It left him hollow. Broken. He'd traded his beautiful, amazing sons for a pretty rock.
"Did it work?" Elrond asked, wrapping his hands around Maedhros, hugging him. Probably the last time anyone would do that other than Maglor. Maedhros knelt, wrapping his good arm around the Elfling.
"It did." He said. Elrond huffed.
"Good." He said. "And if that was all it took to avoid murder, everyone should've done it in the first place." He wiped his face on his sleeve.
"You're going to have to stay with them, little ones." Maedhros said. Elros opened his mouth, ready to argue, but Maedhros cut him off. "No! You know about the wolves and the Orcs, yes?" They nodded. "Thou cannot leave the city. Thou cannot leave it without a trustworthy guard." Maedhros said. "I might not get there in time to rescue thee."
"We will be careful, Atya." Elrond reassured him. "You will know to come and get us."
"You will be happy there, penneth." Maedhros said instead. The Doom wouldn't fall on them this way. They could be safe.
"How can we be happy without our Atto and Atya?" Elros scoffed. "Don't even try this again, Maedhros." He shook his head in an approximation of Maglor. "You can't run 'way from your feelings."
"Young Peredhil, you must come with me." Gil-Galad prompted. Elrond and Elros gave both Maglor and Maedhros tearful hugs. Maedhros watched them from the towers until they were out of sight, then turned to his commander. There was, really, no way he would abandon them. Gil-Galad wanted their sons? He's have to do more than trickery to keep them.
"Take the Silmaril and throw it in a volcano somewhere. Do not touch it." He warned. "It has caused enough pain. It will cause no more." Cursed rock. He hoped he never saw another Silmaril again.
"Yes, my lord." The commander said. "Will you be riding out for the princes?"
"We will watch over them." Maedhros said noncommittally. Best to give him plausible deniability. He and Maglor had their horses saddled in minutes. They shadowed Gil-Galad's men all the way to Lindon. Their bonds with the twins remained open. The two boys chattered through it, deftly disguising fear and grief as they sent images of flowers and waterfalls to Maedhros and Maglor.
It was nightfall when the façade dropped. Elrond and Elros were scared. Maedhros and Maglor crept closer, unwilling to leave the boys without comfort. They reached the twins' room and ducked inside.
"Atya! Atto!" Elrond and Elros whispered, joy filling their watery eyes.
"Missed you." Elrond sniffled, burying his head in Maedhros' tunic as Elros clung to Maglor. "Will you take us back now?"
"We were always going to take thee back." Maedhros promised. "I am sorry that the Oath made us abandon thee."
"Know you didn't mean to." Elrond said. "But it was scary. All the soldiers kept saying mean things."
"To you?" Maedhros asked. He and Maglor exchanged an angry glance. Elrond ducked his head. Maedhros picked him up and Elrond buried his face in Maedhros' shoulder.
"Sometimes." He said.
"They called us bad words." Elros declared. "Atto said we shouldn't call ourselves those things, but they said them." Words flashed through the bond. Half-breed. Mongrel. Fëanorion brat. Maglor growled, his voice making the air hum.
"And they were mean to you." Elrond added. "Said that you were evil and that we were—we were brainwashed!" He looked very offended. Maedhros kissed the top of Elrond's head.
"The adoption bonds prove otherwise." He said.
"Can we go home now?" Elrond whispered, ducking his head under Maedhros' chin.
"Yes." Maedhros promised.
"No." Another voice said from the entrance. Maedhros spun, keeping a tight grip on the child in his arms, cursing his lack of awareness. Gil-Galad stood there. At least a squad of guards stood behind him.
"If you think that is going to keep us from our sons, Gil-Galad, you are sorely mistaken." Maedhros growled. Elrond clung to him tighter, glaring at Gil-Galad.
"You can't take us from Atya and Atto again!" He declared. Elros grappled with his play sword, drawing it from the decorative sheath and pointing it at Gil-Galad from where he sat in Maglor's arms. Maglor pushed the sword down.
"No, little star. Don't provoke violence."
"Atto…" Elros pleaded. "Don't let them take us!"
"Of course not." Maglor promised.
"Let us go and no harm will come to you." Maedhros warned. "I don't want to hurt anyone." There was a quiet scoff from one of the soldiers. Maedhros ignored it, looking into Gil-Galad's eyes. "How many lives would it cost to take me down?" He asked.
"How many would you kill?" Gil-Galad said. "Surely these children aren't worth that much to you."
"They are worth everything." Maedhros snarled. "I would not have given them up if I had any choice. Go! Let us take our sons home."
"Your sons?" Gil-Galad demanded. "These are not yours. They would never love you. You slaughtered their friends, destroyed their city. You forced their mother to abandon them. Why would they love you? How could you claim them after—"
"Shut up!" Elros yelled. He gave a guilty glance towards Maglor, who had often scolded them for using rude words. When he wasn't scolded, he glared at Gil-Galad.
"You don't know anything." Elr0s said. "We love them. They are Atya and Atto and you can't take us away because then we won't get cakes and Elrond is going to apprentice to the healer and Maedhros is gonna teach me swords and everything will be horrible if you take us!" He folded his arms, as if he had just presented a logical masterpiece.
"Brainwashing children, kinslayers?" Gil-Galad whispered, looking horrified. "And I thought you couldn't stoop any lower. What next, torture?"
"Never." Maedhros snarled. "They are not brainwashed. You cannot force an adoption bond. It is always real."
"Maedhros and Maglor adopted us. We'll die if you take us away." Elrond said. They wouldn't die, but they would probably be sick and depressed. Gil-Galad knew Elrond was exaggerating, but he nodded anyways.
"If we allow you to take them, you must accept an envoy from our kingdom to ensure that they are well-treated." He said.
"Very well." Maedhros agreed.
With Gil-Galad's—begrudging—permission, they headed back to the fortress. Elrond and Elros had fallen asleep, so Maedhros and Maglor rode with the twins in front of them, making sure they didn't fall off.
"We could have lost them." Maedhros breathed, finally giving voice to the fear that he had felt all day.
"We didn't." Maglor said. "And the Oath is broken. It won't happen again."
"Never." Maedhros agreed. "For they are far more precious than the Silmarils ever were."