Originally written for a prompt from a challenge set.
Kei chafed at the restraint of the sun keeping him away from Sho's bleeding, coughing self. Glancing up to the sky and praying for clouds every few seconds, Kei paced a short path back and forth, desperate to get to Sho.
When finally it dimmed enough that he could, he was at Sho's side in less than a handful of Sho's struggling, too-quick heartbeats, wrapping an arm behind his head and beginning to cry as the injuries he had taken became clearer.
"Sho. . . Sho." Kei nearly whimpered. "Sho, don't leave me, no, come on. . . You're strong. You can-" his voice broke as Sho coughed his own blood over his lips, the scent barely touching Kei through the despair of watching his little one dying in his arms.
Sho reached up for something Kei couldn't see, choking as he tried to speak again. Kei caught his hand and dragged it to his own chest, rocking himself, terrified and sobbing as he pleaded with Sho.
Sho was his little one, he was- Kei felt a howl catch in his throat. He had been prepared to die today to send Sho back to his little girl. He had wanted to do anything to keep Sho from getting hurt, and when Sho had penned him with the sunlight. . .
Kei rocked himself, cradling Sho closer, knowing that the movement had to be hurting Sho, but also that he was too far gone to really feel it, even if Kei had been able to stop himself. "No, you're too young, I haven't- No. I can't-"
Kei felt his fangs beginning to lengthen in his mouth, and his eyes went wide as they darted from Sho's clouding blue eyes to the length of his dirty, blood-smeared neck, his pulse pounding weakly there.
"I'm sorry." Kei said brokenly. "I can't lose you, Sho, I can't- I can't watch you leave me like this." He stroked Sho's face, remembering brushing away nightmare's tears for the boy and holding him much like this so many years ago.
Sho was far too far gone to make sense of Kei's words, but he spoke them anyway, then cradled his little one, grown as he was now, closer to his chest, and bowed his head, burying his fangs into the thick vein in Sho's throat as gently as he could.
Sho trembled, and Kei cried as his blood welled into Kei's mouth, rich and tart with adrenaline and sorrow. There wasn't much left to pump into Kei's mouth, but he took it, until Sho's heart fluttered, almost stopping.
Kei finally drew back, baring his still-bloody fangs and ripping a hole in his own wrist, pressing it to Sho's mouth, which was slightly open already. Sho whimpered but after a few moments, as Kei's blood spilled from the corners of his mouth, he began to swallow.
Kei rocked him, whining softly and trying not to move too much, to upset his little one. "Sho. . ." Kei breathed, pleading in his mind for Sho not to leave him, though he knew what he was condemning Sho to with this. . .
"I can't let you go, I'm sorry, Sho, I can't." Kei whispered, as his vision went dark for a moment, Sho finally slipping into death, Kei's blood staining his lips. "I'm so sorry." Kei breathed, pressing his lips to Sho's forehead.
He painstakingly dragged himself to his feet, hauling Sho's too-big form into his arms, remembering when Sho had been small enough that this had been easy. He didn't want Sho to wake here, by Son's body, in a pool of his own blood.