This is a profile I wrote for a shinigami OC. It covers how she got her zanpakutou. It cuts off suddenly though, so I'll give you the end of the story. Her zanpakutou is called Kaijou Kasen, and it is a harpoon and whaling lance set. So, here you go:
The final member of Gogyou is Anzu Kaiya (杏怪冶 "Apricot" "Mystery Melting"), the only female member. Hers is the fire-type zanpakutou, and such an unusual one that, rather than simply go into its particulars, we must first describe how Kaiya acquired her blade.
To do so, we must first introduce her inner world, which she named the Yūbae no Umi (夕映えの海 "Sea of Sunset Glow"). As the name implies, it is a sea, one wear the sky is always a brilliant, burning orange. The first time Kaiya ever came to the Sunset Sea, she was eight years old. On arriving, she found herself on the shore of a deserted island with a voice from the ocean beckoning her to come into the water and play. When she waded into the water, she was greeted by a red baby sperm whale, who seemed to be the one calling her. As she reached out her hand to pet his large head, the whale, who was much larger than her even as a baby, bit her leg and attempted to drag her down to the bottom. She struggled frantically and managed to tear herself away before she was drowned. Her leg was broken and as she sat in terror on the beach she heard the voice call to her again, "You got away today, you may get away tomorrow, but I will will get you one day and be free free free."
When Kaiya returned from the Sunset Sea, she begged her mother to save her from Akikuji (roughly, "Red Whale"---"kuji" was Kaiya's mispronunciation of kujira "whale"). Her mother thought she was having nightmares, and so sent her off to the local herbalist, to get something to calm herself down. This herbalist, who Kaiya called Grandmother, was in fact a former member of Gogyou from three generations back (and herself the Fire Gogyou), and somewhat knowledgeable in the ways of zanpakutou. When the girl told her of the dream, she was stunned---the girl, at only eight years old (and which is little more than a toddler's age in Soul Society) was already being drawn into her own inner world, and what was more, had attacked her.
"It is not unheard of," she said, "for a shinigami to see his zanpakutou as merely a tool. But a zanpakutou is not a tool, though it may be used as such---it is a spirit unto itself, and though born from its master, is not the same being as its master. In such cases, the Sword can do nothing but cry out in misery and pain at being used thus, or so I had thought. But, when I consider it, I suppose that the opposite is also possible---that a Sword should want to use its master as a tool, but is unable to because of the master's natural domination over the inner world in which the Sword is trapped. Perhaps, if there were such a sword, he would prefer annihilation, in his masters death, to being always confined in the inner world.
But this Akikuji, as she called him, said that what he desired was "freedom". Not "death" but freedom. Now, from what we understand, a Sword can only ever escape from this world when its master has an unusually amount of strength and is, through his own efforts, able to manifest the Sword spirit in the external world to the greatest extent possible: which is called bankai. But, just as the opposite was possible in the first case, perhaps it is possible here as well---that an unusually powerful Sword-Spirit should try to use its own strength to manifest in the external world, and make its master submit to it rather than submitting to the master, make itself the sword-wielder and its master the sword."
On this hypothesis, the herbalist, (whose name, by the way, was Shinnou (心嚢 "Pericardium), began to take an interesting in the girl. They came up with a strategy for subduing Akikuji---he would have to be hunted down. Shinnou told the girl that, the next time she came to the Sunset Sea, she must avoid the water---for the time being. Instead, she must go inland to wear there were trees and fresh water and begin making a whaling ship and a crew to man it. For the latter need, Shinnou instructed her on how to mold and bake clay with her own reiatsu in a way that would generate moderately intelligent helpers. The construction of the ship and crew took Kaiya most of her teen years, since she was not in the Sunset Sea more than a month out of the year. The vessel she named the Hiwatari (火渡り "Fire-Walking"). She left the crew mostly unnamed, except for her first, second, and third mates, each of whom commanded one of the four whaling boats: 1st Mate, Houshikari (星明かり "Starlight"); 2nd Mate, Zansho (残暑 "Lingering Summer Heat"); 3rd Mate, Baien (煤煙 "Smoke and Soot").
From the age of fifteen to eighteen, Kaiya held stood at the helm of the Hiwatari stalking Akikuji. This meant that, every now and then, Kaiya would enter a coma-like state for two-weeks at a time---which, needless to say, terrified her mother. It was never hard to find Akikuji---he usually seemed to be waiting for her, poking his massive forehead out of the water and glaring. When he breached, it sulfurous fumes rose into the air, poisonous enough to peal off skin and more than enough to melt an animated clay oarsmen, meaning they four little sloops had to approach him with the utmost care. Over those years, Kaiya became a master with the harpoon and and the dart,
(all of which she made herself in her forge on the island) and could hook the any point on the dorsal side of the evilly-glaring whale from a distance of 50 yard.
****************************************
********** ****
At this point, let me make a distinction: the harpoon is a spear that is fastened to a rope and thrown (in traditional, or at least early 19th century whaling) into the whale to slow him down and bring him in range. The harpoon is not the thing that kills. That is the dart or the lance (you can see a picture here:
http://www.whalecraft.net/Lances.html), a which was thrown at the whale to get it bleeding, and then, when it got close enough, jabbed directly into the whale until it was dead. I know, it's seems barbaric, but in traditional whaling done all by man-power, the whale and the whaler were on much more even playing field (i.e., the whale could really fight back with its flukes and teeth, not to mention its ability to swim away) than came to be so with the advent of the harpoon gun and the explosive dart.
****************************************
********** *****
Akikuji's appearance was not different from that of a real sperm whale, save that he was, of course, entirely red---though, given the unfathomable power of the real-world variety, this was little comfort. To the innate power of the species, Akikuji added flukes strong enough to split a modern warship and teeth that seethed with fire and could melt iron. But in spite of this, she and her crew (or at least her mates) had lived through countless attacks on the leviathan, and riddled its back with so many darts that he looked more and more like a swimming hedgehog. And yet, he would not die or submit, and always managed to tear the harpoon out of himself and descend once more to the depths.
Kaiya often consulted with Shinnou, but the latter was baffled by the Sword's behavior, and could give no advice. Also, Shinnou was getting very old even by Soul Society standards, and her mind was starting to go. During her respites from the Sunset Sea, Kaiya would care for the old woman and listen to the stories of her time as a mercenary while the old woman listened to her stories of the sea. They became very close indeed, and Kaiya loved the old woman, and dreaded the day she would leave her. And when she returned from her first voyage after turning 18, the day came. The whole 52th District came out to honor the old woman, as there were few she hadn't helped in some way, and it was Kaiya who was given the ashes, which she kept in her room as she didn't know what to do with them.
When next she came to the Sunset Sea, she saw something strange---a wisp of smoke rising from the inner part of the island. At first she thought one of her mates might be at the making fresh darts, but she soon realized it was coming from a place near a little cave by the northern shore. When she investigated, she found Shinnou sitting impassively next to a campfire. When she ran up to her, the little old woman gave no sign of recognition. She said she a Wise Woman and had always lived on the island.
"And who are you, girl?" the old woman asked in formal tones.
"I am Kaiya," she said plainly, accepting that this Shinnou didn't know her.
"What are you doing here?"
"I seek Akikuji. Me and my men have been after him for years but he will not die or submit. I fear that all we have done has been in vain."
"No such thing, girl, no such thing," she said, becoming casual. "The Red Whale is weak from those darts, if yours they be. But darts alone cannot make him submit---rather, you must pull the thing you seek with your own hand."
"If you are not Shinnou, how do you know what I seek?"
"Because I have seen it. I have seen through the blubber and bones and seen it. I have heard him whispering his true name to himself in the water. I know what you seek, girl, and I know how you shall make him submit. This is what you must do..."
The Hiwatari came to the island and she rowed out to it in her sloop. She looked at her mates and said, "This will be the last time we face him, for I have found out how make him submit. And I must also go alone, with my sloop and my oarsmen."
They frowned at her with their almost-human faces. She went on. "I will hook Akikuji myself, but I will use this harpoon instead of my usual one." Here she showed them the single-flue miro the woman had given her.
Baien said, "The pole is made and the chain are made of ivory. And the chain is only half there."
"Yes, I know," she said. "I will provide the rest of the chain right now." At this, she jabbed the harpoon through her chest and out her back. It was covered in blood.
"Captain!" her mates yelled at once. They rushed to her but she stayed them with her hand. She turned around so that her back was to them, half of the pole still jutting out of her chest, and said gently, "Can one of you pull this out for me?"
Houshikari rushed forward to pull the harpoon out from the pole, but she redirected him, "From the other side, Housh'kari."
"But Captain, that---"
"Please, just do it Housh'kari. This is very painful."
Shunzo, looking more human than he ever had, grimaced as he slowly pulled the harpoon from her back. When the came out, he started pulling out the ivory chain and realized it had more behind it than it should. When he had pulled out enough chain that the harpoon, pole and all, lay flat on the deck, Shunzo said, amusedly, "Captain, how long've you been been hiding that chain in your lungs, eh?"
"I've always had it. It is my soul chain," she said, picking up the harpoon and wiping off the blood with a rag she had handy for just this purpose. When Houshikari examined the front of her, he saw that not only was there no wound, there wasn't even a hole in her clothes where there should have been.
"I will hook Akikuji with this harpoon," she said, "and he will drag me down into the sea. But with this in him, our lives will be connected and I will not drown. Then I will stab him in his three Burners, the seats of Fire in him that run down his belly where no darted lance can reach. Then he shall be vulnerable enough that I may reach into his heart itself and pull out the very center of his life. That is the only way it can be done. Either I will make him submit, or die in the attempt."
Within an hour she had readied herself and her oarsmen. She had to say goodbye to her mates, though---they had been there with her through it all, and clay or not, she cared for them.
"Mates, I..." she began, but Houshikari cut her off.
"We are going with you," he said plainly.
"I've already told you," she said, frowning, "I have to..."
"No. You will not go alone. You are not only our Captain, but our creator, and our lives belong to you, one way or another. So, if we cannot go with you in our boats, we will use smaller vessels."
At this, each of them began to crumble, and then fall entirely apart. In each pile of crumbled clay was a dart---and not a dart like she was accustomed to using, but one more like that used by the Eskimos in their traditional whaling (here's a picture:
http://www.mnh.si.edu/lookingbothway...jects/173.html). Each was emitting an aura: one was glowing with light, one seething with heat, and one fuming with smoke. So her mates would have their way, and join her in their last battle with the Red Whale.
Kaiya set out that day in her sloop with her three mates strapped to her belt. It took only an hour to find Akikuji, as she needed only to follow the smell of sulfur. She first spotted him by the lances poking out of the water like so many cattails, as it was a calm day with almost no wind. The oarsmen put her in striking distance (about 40 ft away) and she went to the prow. She gave herself about 75 feet of chain---and even she was surprised at its length---and readied herself to strike. Just as she was about to go into her throwing motion, Akikuji spoke to her for the second time in her life, doing so, she now realized, directly into her mind, as whale's mouth's are unconnected to their respiratory system, and thus couldn't really speak. He said to her, in a low, terrible voice, "So, today is finally the day."
She hurled the harpoon at him, hooking him a few feet above the left flipper. She could see a kind of flame traveling up the ivory chain from the spot where it had hit. It snakes up the loose chain and crawled into her back and through her spine and into her heart. And then, she exploded. Her entire body was on fire. She dove into the water just as the whale began his descent into the unknown depths of her inner world.
She pulled herself forward. Akikuji glided upward and swung at her with his massive flukes. She only just managed to get underneath the blow, which she noticed was a slow one, even considering the greater resistance of the water. So the old woman was right---he was getting weaker. But even as she thought it, his fiery maw was rushing towards her, noxious bubbles rising from the teeth. She pulled out the Houshikari from her belt and gashed the massive forehead as she swung her herself up onto his back. She felt around for the blow-hole, and when she found it she jabbed Houshikari a few feet behind it, into the upper burner near the diaphram (which, on a whale, was near the blow-hole at the top).
The whale became frantic and started writhing and plunging downward as fast as he could. She pulled out Shunzo and Baien and used both darts like picks to to get to the underside. She had nearly reached it when she saw that they were by a massive reef of red coral. Akikuji flung his huge flank against it, throttling her with blows that ripped through his own soft flesh. She pulled the dart out of him and pushed off against the reef, and, in spite of the gallons of seething blood that nearly blinded her, brought herself directly beneath the upper burner . She forced Shunzo through the blubber into the middle burner near the stomach. Akikuji made sound from his blow-hole, or perhaps from the spermaceti in his forehead, that sounded like a mix between a groan and a cry of rage. That was when she began to notice the water getting much warmer, and looked below.
There, she saw the faint glow of a submarine volcano, the true home, she now realized, of Akikuji. His lung capacity had been transfered to her through the chain, and even if the liquid rock did not burn her to death, the incredible pressure would. She through herself back to the spot where the third burner lay, near the intestines, close to the spot where the tail-fin separated from main body, and thrust Baien upward until her entire arm was engulfed. She him bellow again. And there it was, right where it should be, a long red ribbon poking out from the whale's blubber to where the heart was. She was almost unconscious from the magma fumes when she pulled herself to it and tugged. She pulled and pulled. The lava was at her back.