This is a short one-shot focusing on the death of Mikani (yes, I must admit that the character is quite a bit OOC and very different from the original), according to Matsuda's theory.
Disclaimer: The DN characters displayed in the text are not mine; they belong to their creator Tsugumi Ohba.
He was alone in that small room, not knowing exactly where he was being held. He could not see or hear anything; only his agitated breathing and the voices he heard in his head interrupted the solitude in which he was immersed. Sometimes, every once in a while, there appeared someone with a plate of food, and a voice that asked him about his relationship with Kira.
Kira! Every time they said his name he could feel his voice, soft and clear, become irritated and acquire a slight tone of anger. He hated how he had been treated by that vengeful god, he to whom he had been totally dedicated and who had named him as his equal, giving up his power to him. Yes, he hated him with a passion, could not bear the fact that he had become a disposable pawn in his particular game of chess. No, the person he knew was not Kira, but some dishonorable scum posing as him.
As he thought about it and passed the time slowly, images from the death of Light Yagami, his false idol, came to mind. Whenever he slept or began to think, those memories appeared, memories which were responsible for him being sleepless half the time he had spent in the cell. He saw Yagami's devilish smile, his way with words as he spoke to those present, shots fired in the dark impacting on his chest, the bloodied body, the cries of pain, and the face of powerlessness and fear he wore when he fell to the ground before the astonished gaze of them all.
Mikami rubbed at his sore eyes, tired from lack of sleep, and looked again into the darkness, waiting for something to happen to end the suffering he was enduring. He couldn't bear to live more, he deserved death. He felt that was on the verge of a nervous breakdown and was delirious at times.
"Mikami, N here," the speaker echoed throughout the room, making a shrill sound. "I have another question about the Death Note." I hope you'll be helpful.
"Let me die..." he shouted, as he waited for the laugh to no longer be heard. "I can't stand to live anymore, I just want to relax and meet the true God, Kira."
There was silence for a few endless seconds. Near seemed to be debating which was the best option for him. Yes, he could clearly see the pattern of his thoughts and the dilemma that killing him raised, thus ending the suffering of the prisoner, or extending its life.
"Allright, I'll write your name in the notebook... if you give me an answer to this last question. Is there another book in existence, other than those we know?"
"No, the last book was taken by the shinigami Ryuk. You have the rest." His voice was calm, knowing his fate. He was glad to know that N had understood.
"Thank-you for your help, Mikami. You are free."
The clang was heard again and the usual calm returned. If what N had said was true, he only had 40 seconds of life left, he would die of a heart attack and could join the omnipotent Kira, the true divinity.
25 seconds ...
The seconds became extremely unbearable. He realized his pulse has quickened, he could hardly breathe and his skin was clammy, cold and clammy.
10 seconds ...
He leaned back against the wall, as he began screaming in pain. He felt a strong pressure in his chest and muscles, forcing him to kneel on the ground.
5 seconds ...
He was too tired to fight the pain; he vomited on the floor, filling the room with a foul odor. The voices he was used to hearing became louder, urging him to join them.
2 seconds ...
He fell to the ground unconscious. On the surface he still continued to experience spasms and went through a moment of agony. Light's bloody face swam before his eyes for a few moments, but this time it seemed that his manner had acquired a mocking air.
1 second ...
For the last time he breathed in the remaining air in the room, his heart gave its final beat; he was on the doorstep of death. His eyes widened greatly, showing the pain he was suffering.
0 seconds ...
Mikami felt a heap of fog surround him completely, fast and stealthy. From his position he could only see hooded figures, almost transparent, accompanied by a Shinigami. Yes, he knew he was no longer part of the mortal world and was stripped of all human nature, he was a soul and so were the figures. Walking slowly, he disappeared into the fog, guided by his brethren and escorted by one of the gods of death, Ryuk.