Character Concept - Nee-chan

Yet another character that doesn't have a proper name. 

Her story is really freaking long and this is only one of her many, many faces. I'm gonna try and tell it in as little words as possible.
So, we're just gonna call her Hana (short for Hanayu, my default name). 
Hana was a normal girl, high schooler, average intelligence. But she was very dense and it took her a while to catch on to things. (I wrote this during my church phase (a period of 5 years where I attended church every Saturday night), just btw.) While attending church one night and hiding from her super religious friend's parents she comes across a room that she didn't know as there. When she walks in she finds a boy. He's injured and is wearing cuffs on his wrists and ankles. She instantly panics and tries to help him. Long story super short, he's a demon whose been imprisoned in the church for some time. He's got an insanely uncontrollable darkness that stems from an ancient relic he acquired in the demon's world (a place called Miera). So he's very dangerous. However, his powers and darkness have been sealed within a cross that is hanging on the wall of his cell. It was sealed there by the government of his world after he was arrested and put in permanent sleep as punishment for losing it and destroying stuff and killing people. Obviously he escaped. Unfortunately, the cross has five releases, a release for 5 levels of powers, and the people who trapped him after he escaped jail and fled to the human world left the on the third release, so he is very dangerous to be around. 
Hana didn't now this when she approached him, and he ends up lashing out at her, his magic barely missing her by an inch. He tells her to leave if she wants to live. She doesn't immediately, but after getting yelled at by the demon she does. However, the cross, sensing the presence of a human with a good heart, latches onto her as she leaves, and she accidentally takes it with her. 
The next week she returns to give the cross back. When she approaches the door it senses the cross and opens. Cutting things short again, she can't return the cross, ends up placing back all 5 releases by mistake, continues to talk with the demon (nameless character #144, now dubbed Hide because default) for weeks, and then ends up freeing him. He can reside physically in the cross and they become friends and later develop feelings for one and other
Really long development cut super short. Another demon shoes up, one without a seal on him and with the same ancient evil magic making them really dangerous and a terrible person. This is nameless chara. #145. We're gonna call him Jin. He was Hide's older brother, though not by blood. His mother was killed when he was very young and he doesn't have very many memories of her. Soon after being left on his own he met Hide and they, in time, became each other's family. When they were 8-ish they saw a girl fall from sky and later found her in a dumpster. When she woke up she seemed to have though she died, and bore a large scar in the center of her chest. The two boys were wary of her since at the time when the human world existed people were very religious (some time in the early 1700s)and their race was called "demon" making them a target, and the girl was wearing a cross. After a bit of time they decided to stay together, and the girl turned out to be really cool, having been very close with a demon while she was "alive" and knowing how to handle them. She raised them, working to provide food, teaching them maths and sciences. She didn't have a name so they called her "Nee-chan" (older sister) and everyone else called her "Ane" (another form of older sister). She had to learn how to be  a mother and they were all very close.
However, the government intruded into the land and despite Nee-chan specifically telling them not to go anywhere near it, they, with a group of kids, go to take a look. They get attacked by the people there for trespassing, and are nearly killed. While running away, Jin goes back for a girl that had fallen, and one of the workers nearly stabs him with a sword. The sword never reaches him through, as Nee-chan steps between them and is stabbed herself, right where her old scar is. She wacks off the worker and grabs the two and runs off. Jin is begging her to stop and rest because she will die but she doesn't stop until they are by the hill next to their one room cottage. When she finally does she drops to the ground and dies, telling Jin it's not his fault, that she knew what was going to happen to her. Then she tells them one last time to never go searching for ancient relics EVER. Hide cries over her body and Jin is so shocked he kinda just dies inside. 
They make her a dress and bury her in the forest on their land in a wooden coffin covered in lilies. Afterward they try and make it on their own, and a few years later Jin and Hide hear of an ancient relic that couls bring back the dead. Still shaken from the death of their only family they decide to pursue it. However, the relic is evil and ends up corrupting them. They, together, destroy things and kill people and are arrested. Jin, whose darkness was so deep from the guilt of having "killed" his sister, was imprisoned and not sealed, while Hide was sealed and sent to sleep with hopes of one day being rehabilitated. Jin broke out and set Hide free despite his mind being completely twisted. Time moved different in the prison as to preserve their souls, and they didn't age in the 300 years they were in it. Hide ran away to the human world to try and find some help but is captured by the church and imprisoned. Jin also fled to the human world, but instead looked to cause conflict and hurt people, since he didn't have a seal to control his darkness. 
When Hana first hears the story she is extremely saddened and actually ends up feeling sorry for Jin, who has tried to off her on multiple occasions, believing that that will set Hide's powers free and that he will join her.
Skipping the development with Hana's religious friends and what not, just this bit. She has three friends uuuuuuh, names. Yuki, Shina, and Kazu. Kazu's father is the head of the church or something, and Yuki and Shina are devout. Kazu is obviously devout. When they learn that Hide is a demon they freak out, but Hana keeps them from telling anyone.
Skipping more stuff. 
At the almost end Hana and Hide face off against Jin. Yuki, Shina, and Kazu are present in the room at the time. Releasing Hide to the fourth seal, Hana hopes the battle will end soon. Unfortunately Jin is still stronger, and feeling betrayed by his younger brother he tries to kill Hide. In desperation, Hana steps between Jin's sharp-ass claws and Hide and ends up getting stabbed straight through the chest. She releases Hide's fifth seal, freeing him from the constraint, believing that he can manage his power. She dies in his arms shortly after. Hide gives her body to her friends, and then turns to Jin. Despite Hana's belief Hide can't control the sadness of losing the girl he loves and a terrible battle insures. Soon after Hana's death a girl in a black hooded jacket (white and brown hair spilling from it, rushes into the church and stops the battle between Hide and Jin. She knocks Hide to a wall, making him lose consciousness. She then walks over to Hana's body and smashes it with her hammer. Her body disappearsl into an array of shattered shards. She then faces Jin.  
She talks to him, kinda taunting him, but there's obvious sadness on her voice. Then she calls him "Ji-chan" which is what his older sister used to call him. (She used to call Hide "Hi-chan") The jacket parts and he can see her chest where a large scar is, cut over by another longer one. He realizes it's Nee-chan. He has a sort of meltdown and then they fight. Skipping the stuff here. Jin says some stuff about how he killed her, how she couldn't be alive. And then Nee-chan says "Ji-chan, you didn't kill me all those years ago. But you did kill me today." Jin grabs her hood and rips it off and the face smiling back at him is Hana's. 
By now it should be obvious Hana is also Nee-chan. When Nee-chan smashed Hana's body, her body, with her hammer she sent it 300 years into the past. It spent a few years in limbo, the scar healing, her hair changing color as it grew longer, and then she fell into a dumpster, awakened by two demon boys who'd found her. It took a her a number of days to realize that she had assumed the role of their older sister and that the older sister Hide had spoken of, the one who died, was actually her. She spends the next 5 years with them, not aging a day. After dying the second time saving Jin's life she fell into a perpetual limbo, however she could travel between the dimension called Dead Space, and the limbo. She modified her body to be able to withstand demon magic, so now she can perform demon shit as well as swing that hammer around, and she also gave Jin the chance to escape. Originally she had intended to seal away her emotions for Hide and prevent herself from dying to ensure they would live a happy life. It didn't work out that way. Once she was dead again she made sure that life would take it course the same way so that she could save them both again. 
After fighting Jin and beginning o bring him out of his misery Hana holds him, calming his nerves and the boy breaks down. She, with a new cross, seals Jin's powers to return him to his former self (sorta). While as a kid he was very cheery and loud, after Hana's death he became very closed off and quiet. With his powers sealed he returns to his quiet demeanor. She drapes the cross around his neck. Despite Jin never being very good a controlling his darkness, he was always very good at managing his power, so she believes him to be able to manage his own seals. She then re-seals Hide's power.
Skipping some stuff, like her fixing the church with demon magic. She and Hide and Jin flee the human world for the demon world, where it had only been 20 years since her death (because I am god in this story and I control time). They take Kazu on his request to make sure Hana is still sane, and they return to their house in Miera. Hana resumes the role as Jin's older sister, still calling him "Ji-chan" but also resumes the role as Hide's lover, no longer calling him "Hi-chan." They have a tough road ahead of them as Jin has had no time to grown up since her death and still has many of the issues he faced when she died. Kazu comes to terms with the difference in the "demons" the church speaks about and the "demons" that he now shares a life with. Hana and Kazu do return home every so often, but chose to stay in Miera (until the four eventually link their house to the human world so that they can live in both). In the first two months Kazu spends there he and Jin become very close with one and other (that ship has sailed and I regret nothing...//shot). 
So yeah. This was an insanely condensed version of this story. I could fit four seasons worth of anime into this story. Season 1 would be Hana and Hide becoming close and getting rid of the dumb stereotypes their respective cultures have placed on the other. Season two would venture into Jin's background and the psychological effects of seeing the pwople most precious to him die, and then the really big battle. Season 3 would be the back story of Hana's adventure raising two demon boys. This is important because it shows how Hana has to grow and the differences there are in raising demons rather than humans. As human's don't normally lose it and end up trying to kill you. Also, the level of intimacy between the three that is not sexual but familial (because there isn't enough of that in anime[i'm not being sarcastic]). And also how Hana deals with the fact that the only people who really share her life are Hide and Jin, as she is very well-liked in their tiny town but none of the demons living there are truly her friends. It's like having an entire village filled with classmates you only see once a day and are your friends but not really. Then a fourth season on their readjustment to life after the fact, focusing specifically on the relationship between Jin and Kazu. 
I could literally make four seasons of awesome and I fit the almost full story into this thing here. //mind explodes