The World had ended once in darkness before. Perhaps it wasn't so surprising it was happening again. Despite all their efforts, they couldn't change the cyclical nature of history.

The others were already gone, engulfed by the swirling darkness that had overtaken most of Scala ad Caelum. It was just Kairi and Sora left now. He slammed the double doors closed behind him to cut off the onslaught of Heartless for now, then joined her. She was doing her best to keep her light going, the last pure light in the universe. One glance at his face told her that he wouldn't be able to protect her for much longer. His face betrayed his exhaustion and his hair was damp with sweat.

"Sora," she said quietly. So much could be said in just one word, especially one as precious as his name.

"What is it?" He sat next to her and brushed a strand of hair out of her face. They were by the window of the old study where Xehanort and Eraqus had once spent many a lazy hour playing chess. But instead of a beautiful blue sky outside, darkness covered the land. Everything had all begun here, and now everything would end here.

"I'm afraid we're out of time," she said sadly.

This was not what he wanted to hear. He grabbed her hand and held it tight. "You're wrong. I can still hold them off. I can still fight. I promised to protect you, and I will. No matter what."

"And you have protected me. You've gone above and beyond to keep me safe. But it's time. The longer we wait, the longer our friends' hearts and souls will hang in limbo."

He shook his head, and his drooping spikes went this way and that. "No. They wouldn't want us to die like this. Giving up on the World just because we're the only ones left."

"We're not giving up. We're just… cutting our losses for now."

They'd been in many battles before, but something about this one just… felt different. It was unwinnable in a way not even their battle against Xehanort at the Keyblade Graveyard had been unwinnable. Fate itself was against them, and they'd defied it for so long that it had finally come to extract its toll.

"Kairi, please," he said, his voice anguished. "I can keep fighting—"

"What, so I can lose you too? So I can watch you die before I die?"

"You've always been stronger than me," he choked out. "We both know you could survive me dying. You've had to do it before. But I'm… I'm weak. Watching you die again would destroy me."

"Then we'll die together," she promised, resting her hand on his cheek. "Till death do us part."

Sora was many things to her now—her guardian, her protector, her dearest friend, her fiancé—but her biggest regret was that he would never be her husband. Not in this life or this reality, anyway. But that didn't mean they wouldn't have better luck in the next life, and they could at least exchange vows in this one.

He smiled sadly as he placed his hand over hers. "Till death do us part."

She took a deep breath. She didn't want to get his hopes up for nothing, but she wasn't without hope.

"Darling, listen. My grandmother's story makes me think this isn't goodbye for good. Remember, the World was reborn once before, from the light in the hearts of children."

"That's true. You think… we might be reborn too?"

She nodded. "Maybe the light in my heart, in all our hearts, will help rebuild the World. I know we're not kids anymore, but it's still a story worth believing in."

"Yeah. And if we don't rebuild it, the kids will."

He stroked her cheek, a peaceful look on his face for the first time since all of this began. Looking into his eyes and seeing the endless depths of love they held for her, even she could rest at long last. The World around them faded away as he brought her into his warm embrace and said her name softly, tenderly. This was how things should be. This was how things should always be. Dying didn't seem so scary anymore, not when he was with her and she was in his arms.

Still, there was one remaining fear in her heart, and he sensed it before she even said anything.

"Something's troubling you," he murmured into her hair. "What is it?"

"When we're reborn, how will we find each other again?"

He leaned back a little so he could meet her eyes. "We'll know each other."

"Even if we lose all our memories?"

He nodded. "It's happened before, and yet we've always made it back to each other." She didn't say anything, so he removed his crown necklace and handed it to her, very solemnly. "I don't know that we'll be reborn with anything, but I'd like to give this to you all the same as a sign of my vow."

"And I'd like to give this to you," she said as she handed him her necklace. They helped each other put the other person's necklace on, and something about seeing him wear her necklace as she wore his necklace put her heart at ease.

"There," he said softly. "I swear I'll come home to you, no matter how long it takes."

She nodded and smiled sadly. "It's a promise."

The double doors to the study burst open. The darkness was here. They were out of time.

In their last moment together, Sora brought her into his arms again and kissed her. No wedding vow was complete without a kiss, after all, and how fitting it was for this to be their final act. Love in the face of loss, togetherness in the face of separation, life in the face of death. They held each other tightly, and the last thing she remembered before the darkness took them was his warmth and his smile.

A/N: Thank you to Seaberry-Siren for the prompt!

This is one of the angstier things I've written lately, but it's not without hope! I have ideas for Sora and Kairi meeting again in their next lives thanks to some conversations I had with a friend. I wanted to write those as well and include it all together with this, but I've just been so… creatively dry lately, I guess, and this is the best I could do for now. If I do wind up continuing this story, you all will be the first to know, haha. I don't want to leave you hanging, but I also don't know when I'll have the energy and drive to write at the pace I usually do.

I still have one last kiss prompt left, but in the meantime, if you're wanting to read more SoKai kiss prompts, they include, "A kiss to pretend, "A good morning kiss," "A kiss on a falling tear," "A kiss in secrecy," "A kiss in public," "A kiss out of necessity/A kiss to wake up," and "A kiss for luck." Thanks for reading! Hope you enjoyed!