A/N: Ichi refers to the double-being, the physical and spiritual entity of two people that exist as one. Ichigo is the one protector, the shinigami side, and Ihakai is the one destroyer, the hollow side of Ichi. Ichigo named his hollow side Ihakai, but because they are both Ichi, only calls him Hakai. Ihakai, conversely, just calls Ichigo Go, although when he's being sarcastic, he reverts to calling him "Oshou-sama," or king. If you must look for a pairing in this fic, as many people are apt to do, you can find it in Hakai/Go.

Ichigo trudged home, exhausted. The blood on his forhead, which had been trickling at first, was now flowing profusely, and the stab wound on his left shoulder was blood-soaked and throbbing. The adrenalin from his battle with that last arrancar was gone, and now all that was left was pain.

"Oi, Go, look at you! You're absolutely pathetic. If you had let me fight, you wouldn't have recieved so many stab wounds!" Ihakai commented, manifesting himself with a fragment of a mask.

"Sorry, Hakai. That was my fight. This pain was worth it," Ichigo persisted, shoving Ihakai's soul away impatiently. "I had to protect Tatsuki! You know full well that you are the destroyer, and wouldn't be able to protect her anyway. Your instinct would have been to destroy her, too. That's all you ever do. Destroy, destroy, destroy."

"Well, sorry, Oshou-sama. Shigata ga nai yo."

The two of them were silent the rest of the way home, and Ichi's mask crumbled back into spirit particles, which returned to his eyes. They were greeted at the door by Karin and Rukia, who had felt his spiritual pressure.

"Ichi-nii!" Karin cried, relieved that Ichigo had not disappeared again. She was unaware of Hakai's presence within Ichigo. Ihakai instinctively reared up, sensing a powerful soul. The mask returned to Ichi's face.

"Stay back!" Ihakai cried. "I'm a hollow!" Ichi sunk to his knees, trying his best to suppress his hollow instincts. His mind flashed back to the last time Hakai had been a threat...

He had been frustrated with his inability to protect his friends, and he had gone to the Visored group for help. They had made him do some ridiculous, inane tasks, and eventually had forced him to battle Ihakai within his soul. It had ended in a stalemate, and only Zangetsu's interference had prevented them from destroying one another. It was Zangetsu who had explained Ichi's unique situation.

Zangetsu and Ihakai were both spirit entities that had come from Kisuke's Hogyoku. Because Ihakai was the only one who could destroy Hogyoku, being the Destroyer, Kisuke could not destroy it, so he had to settle with hiding it within Rukia until a felicitous soul for the Hogyoku came along. Rukia, appropriately, when she became a shinigami, got the zanpakutou Sodeno Shirayuki. Incidentially, Shirayuki was a white zanpakutou, and Tensa Zangetsu was black.

The Hogyoku in Rukia's body had made her grow at an astonishing rate; her own Shinigami powers were developing along with those of the Hogyoku. As Rukia trained tirelessly to become a Shinigami, Ihakai trained similarly within the Hogyoku.

Zangetsu, however, didn't know the rest of the story until he had met Go for the first time. He could then sense and piece together the most of what had taken place while he was dormant within Rukia. One day it had come to pass that Kurosaki Isshin, the retired Shinigami, had had a son who had prodigious amounts of reiatsu. To top it all off, he had been named Ichigo, the one protector. He was the felicitous avatar of strength Kisuke had been searching for. Kisuke immediately took protective measures around this hugely important ally. He convinced Kurosaki to take one of his power-draining gigai so that young Ichigo would not sense something suspicious about him. Sensing spiritual powers would draw out his powers and then in turn, draw hollows to him. He also took away Ichigo's body, and stuffed his soul into a similar Gigai. Finally, he got Kurosaki and his family to move out of Kurosaki's squad's district and into the thirteenth squad's district, where Rukia and her captain were in charge.

Eventually, though, it became apparent that this prodigy could see ghosts. Kurosaki and Masaki were warned, and they took protective measures around their precious Ichigo. Masaki enrolled him in a karate dojou, and Kurosaki anonymously hired a low-level Shinigami to specifically go around hunting hollows and performing Konso on any ghosts that happened to be around. Eventually, though, Kurosaki's credits for destroying infamous hollows ran out, and he was unable to pay the Shinigami further. Ichigo began to see ghosts more and more often, and eventually was drawn in by the Grand Fisher. Masaki, who could barely see hollows, offered her life to safe his, knowing that he must live on to protect everyone else.

From then on, everything was a complete disaster. Though Ichigo had the gigai, it was by no means able to suppress all his reiatsu. Ichigo, of course, did not know of his reiatsu and so leaked it out around him. Arisawa, Keigo, Inoue, Sado, and Mizuiro all began to unconsciously gain reiatsu of their own to guard them against his. Orihime, being the daughter of a Shinigami, gained reiatsu more quickly than anybody else, and so when others thought of Ichigo as scary (being impressed upon by his now immense reiatsu), Orihime just found it funny. Sado sensed this power in Ichigo and was immediately drawn to him, and Ichigo saw power in Sado and was conversely drawn to him as well.

After Rukia, on orders from Soul Society, came to exorcise the hollow, Ichigo's gigai had started sapping Rukia's power when it could no longer touch Ichigo's. When Rukia had tried to infuse Ichigo with half of her powers, the gigai absorbed the rest as well, and inadvertently took the contents of the Hougyoku. Ichigo, now too powerful to be contained any longer, had exploded from the bankai as a shinigami. However, that was the first time he was mobile, free of his gigai, and so, shortly afterward, he lost consciousness. When Kisuke had offered Rukia a gigai, he had also given Ichigo his human body back. That's why, when Byakuya had cut off Rukia's Shinigami powers, Ichigo didn't die or become a normal soul, but became chained to his body.

Ihakai had come from the Hougyoku. The reason Aizen had so mysteriously commented that the Hougyoku was smaller than he expected because Ihakai had no longer been in it. XP Rukia's soul, which should have been severly damaged when the Hougyoku was removed, had remained unharmed because the true object of the Hougyoku was already gone.

After Ihakai and Ichigo had learned of this, Zangetsu had chided them both for fighting each other. "You two are like little children," he'd lectured, "Always fighting over things. 'Mine, mine, mine. You know, instead of fighting over the body, you could share it."

"But Hirako-"

"No, Ichigo, Hirako is a visored. He willingly took on a Hollow soul in order to become more powerful. Because he took on a Hollow soul, he intentionally took on one less powerful than himself. You, on the other hand, unintenionally took on a Hollow soul that was already as powerful as yourself."

"But I-"

"No, Ichigo. You and the hollow got this body at the same time. Ichigo, you were in a gigai to mute your power, and the hollow was in the Hougyoku with me. Kisuke intended the body for both of you, and this world for me. He just wanted me to wait until you were ready to learn to share."

"What is this, Kindergarten?" Ichigo had muttered, finally conceding defeat. He had opened his physical eyes, and gotten to his feet jerkily. When Hirako had asked him if he felt better, he had childishly stuck out his tongue and replied, "Yeah, thanks. I've learned how to share now," and left without another word. After a couple of blocks, he had found an empty building and gone to sleep, exhausted.

When Ichigo had woken up, he and his hollow had had a long talk in Ichigo's soul world. Ichigo had eventually come to decide that now that his hollow and he were quite literally soulmates, the hollow had a need for a name. He had thought back to what Ikkaku had said about his own name. "Men with Ichi in their names are always powerful." So his hollow had better have an Ichi in his name. Ichigo had thought about his own name. Ichi...go. The one...protector. That certainly wouldn't work for a Hollow. They were too destructive... Destructive...The hollow was meant to destroy...so he was a destroyer...the one destroyer...Ichi...hakai...Ichihakai? That didn't go too well in his mouth. He wanted something shorter. But what could possibly work, then?

"How about 'Ihakai?'" the hollow had suggested thoughtfully. "It gets the point across, and it's not hard to say." Ichigo had agreed.

"So, King, what're we gonna do now? I don't really want you going around, killing hollows, but you don't want me to go eating Shinigami, either."

"We'll figure that out later. First I've gotta get home, though. My folks'll be missing me."

Missing Ichigo indeed. Yuzu, Karin, and Isshin had all taken off. He had gone to sleep...but had been awoken again by the feeling of another arrancar nearby. He and Ihakai had fought each other as well as the arrancar, and therefore were wounded very badly by the time they had protected Tatsuki. They had brought her home and then trudged off in the direction of their own. However, then Ihakai sensed Karin's spiritual energy, and his hollow instincts told him he was...hungry.

Ichi shook off this memory and concentrated his will. The mask crumbled back into spiritrons and returned to his body. The strain was too great for him, however, and Karin had to jump to catch him as he slumped to the ground, unconscious.