Misaki thought the rage was the worst of it.
It's something about Saruhiko, something about too many years together or just some uncanny intuition on the other's part that lets him slice clear through Misaki's restraint as if it wasn't there, until he barely even has to smile to set the other off. It's like being consumed alive by his own flames, as if Saruhiko retained the ability to envelop Misaki in the agonizing heat of Homra's skill in spite of the burnt-out mark on his shoulder, and when Misaki sees red there's nothing he can do but attack. Usually this turns out the worse for him, with Saruhiko's knife in his shoulder or Saruhiko's arm bracing against his throat, but it never matters at the time; it's not the pain that Misaki fears, either during or after, as much as the uncontrolled fury that takes over and makes him a puppet with Saruhiko dragging careless on his strings.
He doesn't know what makes this time different. Maybe Saruhiko is tired, less quick to catch Misaki's attacks on the edge of a blade or not quite as fast to dart backwards and out of range of his bat. Maybe it's something as simple as Saruhiko's glasses being smudged, that he misjudges the distance between Misaki's weapon and his own hand. Misaki doesn't care at the time. What he cares about is the way his swing connects, the crack of impact and the sharp hiss of pain even Saruhiko can't restrain when he's not expecting it. It goes through him like lightning grounding out on sand, turning his awareness crystalline and sharp-edged, and when he swings again it's a backhand so fast it hits before Saruhiko's dropped knife has yet hit the ground.
It's not a fight, after that, not a duel as much as a beating. The rage in Misaki's blood is enough to push him forward, to tear fury from his throat with curses too fast and hot to be understood, backdrop for the two-handed swings of his bat that ground out at Saruhiko's upraised arms, smash into his fingers, tear apart the other's makeshift defense as easily as Saruhiko tears down Misaki's self-control. Each arc stalls out with a satisfying impact, the give of blood and bone instead of the skid of a knife Misaki is used to, and Saruhiko is responding, too, giving up tearing cries from his throat that sound as agonized as Misaki wants them too, whatever sultry overtone he usually achieves drowned out by the instinctive noise of true pain.
Misaki's not thinking when he swings the last time. Saruhiko has his hands up in front of his face, the white of his sleeves stained crimson with blood from injuries Misaki doesn't even pause to see. It seems right, to stain him with the color of the clan he so casually gave up, and it's the taste of avenged betrayal on Misaki's lips when he swings again. The bat connects with Saruhiko's wrist, the impact pushing it aside like a leaf in the wind, and Misaki can hear the dull thud of the wood crashing against Saruhiko's temple. There's a moment of silence, like the entire world is hanging paused for the length of a heartbeat; then Saruhiko's eyes roll up, his whole body drops boneless to the ground, and everything in Misaki's body turns to ice.
"Saru," he says, the bat dropping from numb fingers to clatter forgotten to the ground. It's his knees that give out then, drop him skidding to the ground so he would feel the skin tear if he could pay attention to anything but the ringing in his head. "Saru." His hands are shaking when he reaches for Saruhiko's face, pushes the dark of his hair back from his slack features; there's a bruise coming against the sweep of his hairline, the damaged bar of his glasses cracking apart at the touch of Misaki's fingers.
"Oh fuck," Misaki says, fast and rushed and shaking. "Fuck, fuck, Saru, goddamn answer me you fucking masochist." He fumbles his fingers in against Saruhiko's throat, feels for a pulse; it's there, hard and fast with adrenaline, and that helps, a little. "Saru."
Saruhiko makes a sound, a faint noise against the ground, and something in Misaki breaks, cracks open like an eggshell caving in to a hammer. His next breath burns fire in his lungs, scorches him raw inside his chest, and when Saruhiko opens his eyes to blink up at him it's Misaki's vision that goes blurry.
"Shit," he says, and "I'm sorry," and he can't see, he's ducking his head and clenching his teeth like that will somehow stop the tears in his eyes.
"Misaki," Saruhiko says, lilting the name slow over his tongue. "Weren't we fighting?"
"I'm sorry," Misaki says again. "I thought I had killed you."
"You could have," Saruhiko says, his tone making the statement a suggestion. It slips into Misaki's blood, another sliver of ice to chill the burn of guilt all through him. "Just swing a little harder next time, Misaki."
"Fuck," Misaki spits. Saruhiko's looking at him, his eyes dark and hazy without the cover of his glasses to bring them into sharp-edged focus, and Misaki doesn't want to see the heat in them, the low burn of pleasure borne from the same thing freezing him into horror at himself. "I don't want to kill you, Saru."
"You don't?" Saruhiko's hand comes up, his sleeve dark and wet and fingers bruised purple and blue with trapped blood. Misaki grabs at his wrist in an attempt to hold him down, to stop the motion that must be agonizing, but as his fingers tighten Saruhiko shudders, a motion through his entire body that converts to an overheated moan on his tongue. Misaki flinches away, drops his hold, but Saruhiko's throat holds onto the sensual appreciation of the sound, laces his words with it as he continues. "What about what I want, Misaki?"
It's Saruhiko's laugh - hot and hysterical and sincere - that is the worst of it.