Disclaimer: I do not own the anime Bleach or anything affiliated with it. Anything not from Bleach, rights go to the designated owners. I only own the Black Hollow (kinda a spoiler, but it is obvious, right?) and it's 'abilities' (you'll see what I mean later on ;P).

I got the idea when I was walking to school a while back, but I've finally formed a story about it. Hope you enjoy!

Brief: Karakura's had some strange things happen to it before now, but nothing on this scale. How will Ichigo and Rukia defeat the menace when their very allies could be against them?

Warning(s): Swearing and cursing throughout, unsure how frequently.

Bleach: The Black Hollow

Ichigo yawned as his eyelids drooped. School, as per usual, was boring. The lecture was a drag this morning but nothing compared to English with their new teacher, who could drone on monotonously for so long it seemed it never ended. Glancing to his right, Ichigo could see that Rukia was feeling the same way; bored. Her blue eyes glazed over as she sketched a cartoon rabbit in her book.

Ichigo averted his eyes, not wanting to make a comment about Rukia's rubbish drawing and being shown up in class. Luckily for Ichigo, it was Friday, last section, which meant only one thing; they'd soon be out of the boredom-laced room and home free for the weekend.

The sharp abrupt ringing of a bell broke Ichigo's train of thought as people began to grab their bags and leave.

"Finally, I thought she's never shut up." he muttered to Rukia, who had to stifle a grin as they walked past the woman in question.

"ICHIGO!" Keigo came charging from nowhere towards Ichigo, only to be met with a clothesline off of Ichigo's arm.

"See ya, Keigo." he replied as his insane friend clutched his face.

"He never learns, does he?" Rukia said calmly when her soul-pager went off. She frowned at the screen.

"What is it? A Hollow?" Ichigo asked.

"I don't know. The pressure seems... different. We should check this one out."

Ichigo nodded and took out Kon from his bag.

"I can breathe again!" the lion toy yelled, before turning some abuse to Ichigo. "Honestly, I could suffocate in there, idiot! What'd you do without faithful Kon, eh?"

Ichigo decided to stop it there, sticking his hand into Kon over-sized mouth and retrieving the capsule inside.

"Disgusting." Ichigo growled, rubbing the capsule against his shirt before popping it into his mouth. Rukia did the same for another capsule, this one containing 'Chappy'. The two were released from their gigai and hurried off towards the Hollow sighting.

They reached the park and came to a halt a few metres from a grey-blue haired man. He looked about mid-twenties from the back, clad in the soul reaper uniform with a zanpakuto at his side. Ichigo wasn't convinced that he had dispatched the Hollow and called to the stranger.

"Names yourself!" he yelled at the man. No response. "I'm Ichigo Kurosaki, substitute soul reaper, and this is Rukia Kuchiki, squad 13. Now identify yourself before I beat it out of you."

The stranger laughed and Ichigo cautiously wrapped his fingers around the grip of Zangetsu.

"You sound confused." the man said. Something about his voice wasn't right, like it was two voices competing for dominance. He knew it from something, but he didn't know what. "You see, I'm no ordinary being. Not like those pathetic arrancar, though. Let me show you, Ichigo Kurosaki, what I mean."

The man turned and Ichigo's eyes shot open wider than ever. Rukia was just as, if not more, shocked about what she saw. The man seemed normal from the back, but from the front he was different. From the neck down, he was nothing special – a few tattoos down his exposed forearms and chest, otherwise nothing – but above the neck line, he wore a mask. The black sclera and piercing red irises made it obvious enough, but he was different. The mask looked like a replica of Ichigo's Hollow mask but with the red veins on the both sides symmetrically...

And the white had, for reasons unknown to the pair, turned dark grey-black, not as dark as the sclera but with a few shades between them.

"A... A black Hollow?" Rukia stuttered. Ichigo scowled and released Zangetsu from it's sheath of cloth.

"Enough talk. Just what the hell are you, a vizard?" Ichigo growled.

"I'm no such thing, nor am I a soul reaper or an arrancar." The creature growled back, the piercing eyes locked onto the orange-haired teen. "My name is Hollow 666. But you won't have to remember that, you'll be dead long before then."

It drew it's blade and muttered a chant, running his left hand over the blade whilst gripping the hilt in his right. The blade began to glow red.

"Growl, Destroyer!" 666 yelled, the blade turning into a black ash flurry, like Rangiku's Shikai release.

The ash cloud raged towards them but Ichigo released a black Getsuga Tenshou and swatted it away. In the disturbance, he called his Hollow mask into position. He roared as the black energy rippled from his blade, sending another blast towards the Hollow, but it missed.

"Now you've forced my hand, Kurosaki. Don't say I didn't warn you." the Hollow snarled. "Bankai!"

A ripple of energy erupted as the Bankai formed. Ichigo took this opportunity to release Tensa Zangetsu and finish this fight. The smoke at each end cleared. Ichigo wielded the black katana-like zanpakuto that was Tensa Zangetsu while Hollow 666 wielded...

Ichigo could believe his eyes, but the Hollow was holding the Bankai form of Zabimaru, the black bone snake with a blood red mane snarled at Ichigo as it raged forward. Ichigo jumped aside with lightning speed and struck the creature with his blade and Tenshous but it was no good, just like against Renji's original Bankai.

Rukia watched the battle rage on with wide eyes. How can a Hollow have a zanpakuto? And why is it's mask black? These thoughts and many others whirled through her head as she stared at the scene before her as it unfolded.

"Rukia!" Ichigo yelled, locking blades with the Hollow again. "What the hell is this thing?"

"Oh, just because I'm a full Soul Reaper, I'm supposed to know, right?" she shouted back to him.

"There's no need to be so pissed. Just let the Soul Society know!"

Ichigo dodged another strike from the snake as it whipped in for a potentially fatal blow. Suddenly the snake broke down into the original, unreleased zanpakuto. 666 laughed.

"Time's up, human." it said. "I'll return soon enough. Until then, a parting gift!"

It threw a Tenshou from it's own blade, red in colour, and Ichigo, not expecting the attack, took it full on, shattering his mask and sending him to the ground. With that, the Hollow vanished into a portal and sealed it on the other side.

Kisuke's shop, back room

Ichigo awoke, his left shoulder bandaged, with Rukia, Renji, Chad and Orihime around him. He sat upright, despite the objections from Rukia.

"So, no one knows what the hell this thing is then?" Ichigo asked, after Rukia had explained the situation.

"That's right." Renji replied. "And no one knows how it's zanpakuto can take the form of any other zanpakuto, but the Department of Research and Development are working on it as we speak."

"That's good."

"Ichigo..." Chad said suddenly, not looking at his friend.. The orange-haired teen looked at the larger teenager. "I'm sorry. I should have been there for you, like you would have been for me. I..."

Ichigo stopped him there.

"It's ok, Chad, there's nothing that can help that now." He smirked reassuringly to the giant, who felt like the pact he'd made with Ichigo had been broken. "We'll get him next time."

"Next time?" Orihime said. "What do you mean?"

"There's no way something like that would stay hidden for too long." Rukia said, arms folded. "We'll have to be on high alert for it."

Unknown area, Unknown dimension

Hollow 666 lay in his chamber like the other test subjects. Of all of the Hollows to be tested, he was the only success.

Suddenly he was carried off and tested, shocked and slightly tortured before being thrown back into his cell. Beneath the mask, a grin formed.

Let them have their fun experimenting for now. When the moment comes, I'll crush them all like the vermin they are, the Hollow thought as it lay it's black-mask clad head on the cold stone floor and drifted into sleep.

Ok, this is my first Bleach fanfic and, as with all the other fanfics I've done, constructive criticism would be appreciated in any form, so please review.

Tell me what you think should happen,

What shouldn't happen,

Anything you like!

Until next time, enjoy!