This is an odd idea that I came up with around three in the morning. It wouldn't leave me alone, so I just had to type it. Inspired partially by the song "Missing" by Evanescence.
He'd felt an odd sense of relief when he'd returned with Yugi and the others from Egypt (never mind that he didn't remember how he got there in the first place). These days, he hung out with everyone more often, going to the arcade or just standing around after school talking about whatever random topic was brought up. There were times when he'd reach up to brush a hand across his chest. He didn't know when or why he had picked up this habit, although he had seen strange emotions flash in his friends' eyes when they noticed him doing it. Was it sadness? Pity? Worry? He couldn't think of why they'd be looking at him like that in the first place, and couldn't shake the feeling that they knew something that he didn't. He had been happy for the most part, but gradually that emotion began to dull. Why? He was closer to his friends than he had ever been. Yet, deep down, what troubled him was that he couldn't seem to remember why he had been distant from them in the first place.
As time passed, he began to feel odd in the mornings. It was as if he had been having a dream during the night, but couldn't recall it. For some reason he felt the dreams, if he did dream, were important somehow. His friends were concerned since he would tend to space out in class often. He always told them not to worry, despite the fact that he was worried himself. It wasn't just the days that were troublesome. He'd lie awake in bed for hours before he fell asleep.
This was one such night. His subconscious acknowledged a slight pain in his chest and a hand brushed over it thoughtfully. His left hand. Why did that have any significance? He groaned in frustration and his hands fisted in the light blue sheets that covered him. He tossed off the said sheets and made his way across the apartment to the bathroom, his bare feet not making a sound on the dark blue carpet. He flicked the light switch on in the bathroom, then turned on the faucet. Cupping his hands so that they filled with water, Ryou brought them up to splash his face. After shaking out his dripping wet bangs, he unbuttoned the top of his pajamas, letting the article of clothing slide off his shoulders and onto the cold tile floor. He walked over to the full-length mirror and stared at himself in it for reasons he didn't know. He had to shake himself back into reality when he realized he'd been staring at a small horizontal scar on the upper part of his left arm for over a minute. He practically growled in agitation. Why couldn't he concentrate? Why couldn't he remember? By this time, he was already back at his bed, proceeding to flop down on it and then pull the sheets over his half-naked form. He stared at the ceiling for a little while longer before he felt sleep tugging at him. The last conscious thought he had before his eyes slid closed was 'Isn't something missing?' A single tear slid down his cheek as sleep claimed him.
A cold breeze suddenly blew through the apartment. It was strange, considering no windows had been opened. A barely visible transparent figure manifested itself by the sleeping teen's bed. It resemblance to Ryou Bakura was striking, although the figure looked much more menacing. Now, however, its eyes were unreadable, almost soft. The figure reached down and stroked the boy's cheek, raising and eyebrow when Ryou leaned into the almost-touch. The figure lowered to its knees and pressed its lips against the warm, soft ones of the sleeping teen. A disembodied whisper filled apartment number 601. 'Goodbye, Yadonushi…and…I'm sorry…' With that, the figure disappeared.