The attacker turned, kunai in hand, as he blocked Kakashi's blow clumsily, gaining more and more expertise, using as if it was a sword, due to the rush of adrenaline. He wasn't as apt as a ninja, through luck and a sheer force of will to block Kakashi's attacks. Kakashi couldn't risk a ninjutsu because they were in the boy's dorm, with civilians and his charge in it. As a result he was confined to taijutsu, and while Sirius Black may have been seemingly scrawny from years in Azkaban, he was surprisingly fast and dexterous when it came to protecting his life with a blade.
Kakashi had his hands full as well, attempting to avoid the beds of the sleeping children while Black was under no such constraint and attacked him ferociously. Forced back against the Weasley boy's bed, sparks flew as the kunai clashed together with each block. Sirius was growling like a mad dog under his breath, a growl that grew louder as he saw an opening and opted to take it, lashing out with a kick that would have knocked the wind out of the guard. Caught by surprise, Kakashi dodged, only to nearly lose his balance. Black slashed at him, and sent Kakashi's kunai flying to embed itself deep into the dorm door.
Kakashi caught Black's wrist as the other man attempted to stab him. From then on, it became a struggle to either throttle each other, or to gain purchase to the kunai to stab each other. Sirius' firm grip weakened as Kakashi tried to crush his wrist. Their frantic flailing and struggles resulted in the kunai, sent flying by a kick, slashing through the Weasley boy's curtains. The boy awoke with a scream, catching both the fighters off guard. Taking advantage of the moment, Sirius Black kicked the guard in the groin, causing him to keel over. As the guard bent over slightly, Sirius followed him with a sudden transformation, and as a dog attempted to rip the guard's throat out.
Raising an arm, Kakashi blocked the furious assault from the Grim-like creature. Caught off balance, he fell down the stairs, he and Sirius Black still rolling and they crashed straight into the Gryffindor Common Room. Kakashi, unfortunately, met the wooden frame of the armchair, no longer squishy, with his arm. A resounding howl of pain and triumph echoed as the Grim landed straight on Kakashi's stomach, knocking the wind out of him before running pell-mell out of the room and most likely, out of the Castle.
Kakashi managed to use his other arm to prop himself up, holding himself carefully.
Bruised, battered and injured.
Attempting a one-handed seal, he tried to send some Kage Bunshins after the escaping convict, only to find out that his control wasn't accurate enough without his other hand to create the clones. Drained, he only managed to level himself up in a standing position as he tried to limp after the convict, who was long gone. He could not summon the clones, he could not attack from a distance, and overall, the only thing he could be proud of was that Black had not been able to be near his charge at all.
The screaming of the Gryffindor boys who had been witness to the fight brought Percy the Prefect running to the dorms, only to follow the anxious students as they rushed to the injured guard, whose arm was clearly broken as it hung limply from his side.
"Someone get Madam Pomfrey!" Ron shouted frantically as Dean Thomas rushed out to the infirmary, clad only in his bedclothes.
Harry looked in shock at the man who had saved his life, eyes narrowing in a resolve to get even with Sirius Black for this. Moving toward the injured guard, he and Ron tried to support the man's other side, to help him into an armchair to rest while the other students went for the teachers.
Harry looked worriedly at the guard as the teachers came in. First, Madam Pomfrey with Dean who came bustling in a small cup of Skele-Gro and in her other hand, a bag of bandages and wood for a splint. The guard did not even hiss in pain as the worried nurse made a 'tut-tut' noise under her breath and tried to set the bone as gently as she could. She had forgotten the anesthesia but the guard did not seem to be complaining. Ron was dead pale as he realized how close they had been to possible death.
"Bloody hell Harry! He could've killed us if the guard wasn't here!" Ron said, pale as a ghost.
"Yeah." Harry replied. "And now we have to look out for the guard until he gets better. I'm not leaving him alone like this when Sirius could come back and finish him off at any moment."
Ron nodded, eyes narrowing in determination as he moved to Kakashi's right. The guard shook his head. "I'll be fine," His voice was raspy. "as soon as my arm heals. Do you have anything to make it heal faster?"
Hermione asked him in shock. "Why didn't you use one of your wandless magic abilities?"
The guard rolled his eyes underneath the mask. "Because my spells could've killed Harry. They're not supposed to be used in close combat situations with civilians in the way. I didn't want to hurt anyone but Black, so I had to use unarmed combat."
"Rest assured." Dumbledore said firmly. "This will not happen again." He seemed to be there instantly. No one noticed he had come inside until he actually spoke. Upon which Snape, who was offering another Skele-Gro potion to the guard, smiled grimly in satisfaction. Sirius Black would never be able to pull this kind of stunt again.
Kakashi swore to himself to work out even if it was winter. He couldn't afford to be caught in such a manner again. He ground his teeth as the piercing pain in his arm indicated the bones were re-growing themselves to their normal configurations.
Snape looked at the guard with grudging respect and admiration in his eyes. A new ally against Black. Just let Lupin try to slip anything past this fellow. Severus smirked as he imagined the confrontation. He'd have to inform the guard to dip his knives in silver, just in case. Moving to the door, the Potions Master eyed the embedded kunai with some trepidation as he reached out and tried to pull it out of the door. It was firmly lodged, and it took him quite a while to work it out.
He returned it to the guard with a grudging, "Nice job. A pity you weren't able to finish it."
Kakashi shrugged and said. "Next time, Black will not have the protection of being in the civilian's room. I intend to make sure he never gets near this area again."
As Kakashi recovered, he was surprised to be congratulated by the portraits and he could see an air of approval in the whole school. Sir Cadogan was fired (which he was thankful for if only because the knight was so damn annoying.) The Fat lady was back, but she wanted the guard (or one of them) to stay with her as much as possible, openly jittery. Still, there was an air of pride as the Gryffindors watched their guard.
Their guard, dammit.
The other House guards hadn't done anything yet like theirs had.
Kakashi viewed this with a mild air of indulgence. Kids were so cute, just like puppies. Maybe when he was old enough to quit ANBU, he might pick up some puppies of his own. He just hoped it wouldn't be an Uchiha. That clan was notoriously stuck up (except for Obito) and he still wasn't on good terms with them with the whole 'You stole Obito's eye' fiasco.
The Weasley boy had become an istant celebrity, recounting the parts of the fight that he managed to see, that no one else did.
"And you should've seen the guard! He was so cool. He was blocking every one of Sirius Black's stabbing attempts with his kuh-nai thing."
Kakashi rolled his eyes. The boy still managed to garble the name of such easy pronunciation. Honestly, these foreigners!
"It's kunai, Ronald." Kakashi said, amused more than anything else. Ron flushed and nodded. "Yeah, that's what I meant."
Kakashi patted the boy on the head with his good hand before walking off to check on the other students again.