"Denial."
The word is dripping with venom, with claws and teeth and glowing yellow eyes, and Riku takes a step back – afraid, and now that he's acknowledged that forbidden fear, he crumbles a little bit more.
"Denial."
The word is spat again, and a cruel smirk shows him sharp teeth that wouldn't be out of place on a tiger, but they're not on a tiger, they're on a man, and this man has him cornered, bruised, and broken.
"You can't accept that your heart is only darkness? You're weaker than I thought, Riku. Maybe I should go after Sora instead… he would be so fun to break. Wouldn't it be pretty, Riku, to see that light extinguished?"
Riku grits his teeth and makes a fist, sea-green eyes flashing and for a moment, he is the tall, confident heartthrob of Destiny Islands. "Don't you touch him, you piece of shit."
A gloved hand reaches out, caressing his face, and Riku can do nothing to stop it because it's only a shadow, but it's a shadow with flesh and bone.
"It seems you have some strength left after all. It seems I struck a nerve… How does it feel, Riku, to know that you're hurting his light when you touch him? How does it feel to know that you're poisoning him?"
"Shut up! I love him, you bastard!"
There is laughter; cold, cruel, malicious laughter, and Riku shivers despite himself, but those sea-green eyes are still defiant, still angry, and the shadow pauses before sneering at him.
"Fool. The darkness does not love – it consumes."
And Riku wakes up, thrashing at a shadow that isn't there because his lights are all on, sweating and crying dry tears and swearing because it isn't true, it isn't true, and Sora is trying to calm him down, placing gentle hands on his shoulders, looking at him with sky-blue eyes and whispering "It's okay, it's okay" over and over again. Riku lets himself be held, lets himself go back to sleep with Sora's arms around him, but the shadow is still there, lurking, waiting.
The shadow is waiting for Riku to consume himself, and as worry over his relationship with Sora ("I don't want to hurt him") grows, it knows that it won't have to wait for very long.