AN: This is my first Death Note fan fiction; I finished watching the series not too long ago, and after multiple viewings of the final scene in which Light dies, I just knew I HAD to make a story about what he thinks during his final moments. So, without further ado, here it is :) Hope you enjoy!
Clutching his left shoulder, 23 year old Light Yagami ran for his life, each step drawing from him a laboured breath as he struggled to find shelter. He occasionally stumbled, but quickly regained his footing and continued running. He knew that Aizawa and the others would be after him, and he had to make sure that he wasn't found by them. As he ran, he thought about how it all went to hell, how his plans for a utopia, a perfect world which was full of honest and hard-working people, were crumbling to dust all around him. He envisioned the past, all those years ago, back to the day when he had first found that accursed notebook. He could see, in his minds eye, the innocence in his own eyes as he walked back from school, thinking about the notebook and what it could do. He wept silently, sobs racking his body as he continued to run. He realised, at that moment, that he regretted everything.
He regretted becoming Kira, he regretted killing innocent people like Ray Penber and his fiancé, Naomi Misora. He regretted manipulating and using people like Misa and Takada, people who were loyal to him until the very end, and in spite of their loyalty, were just tossed aside like rag dolls when their usefulness diminished. Most of all, he regretted killing Ryuzaki, probably one of the only people whom he considered something close to a friend, and he, as Kira, simply did away with him like some stain, some imperfection which had to be removed in order to create his new world. He saw something in the distance, a figure walking with a book in his hand. This person's eyes were innocent and pure, free of any evil or maliciousness. As Light ran past him, he realised with a wrench, that the person was him. What he was before he became Kira.
The sun was setting, both on the world and Light's life, as he felt his heart pumping weakly. He knew his end was near, and he remembered, though all the pain, how Ryuk said that he would be the one to kill Light by writing his name in his Death Note. After coming to another warehouse, Light's run had slowed to a limp, as he struggled to find shelter. Not willing to give up, he limped, slowly, to find a resting place. His eyes coming to rest on a set of stairs, he laid himself down on it, when his eyes suddenly widened, and he felt his heart stop beating. He knew that Ryuk had written his name in his Death Note, and that he would die of a heart attack, just as how the various criminals he killed in his quest to become God did. He blankly stared at the ceiling, wondering what would happen after he died. In the end, Light had failed. The world would return to normal, the crime rate would increase, and Kira would soon be forgotten. Ironically, his entire body was bathed in light, light which he would never set his eyes on again. As he lowered his eyes, he saw a figure dressed in a white shirt, and with his hands in his pockets, staring down at him with a sad expression.
It was L.
Upon seeing him, Light knew that L had won. Even though it cost him his life, he had brought Kira down. His body no longer willing to withstand the pain, he slowly closed his eyes, a peaceful expression on his face as he passed from the realm of living into the realm of Mu; the realm of nothingness, and his resting place for all eternity.
So, that's it. This was something I came up with more or less on the spot, so forgive me if there are any lapses in the actual chain of events. Thanks for reading and I hope you enjoyed it! :)