Nagasaki, Yuki
Aliases/ Nicknames:
Yuki isn't picky about nicknames so he is likely to have many.
Physical Description:

Yuki is around 5' 10" weighing about 150 lbs. with a normal build. He black hair and bright green eyes.
Zanpakuto:
Amatsu Tenshi (Heavenly Angel)
Released by the command Sacred Light Shine Through The Darkness.
Zanpakuto Spirit:
Amatsu
Shikai: Achieved
Yuki's Zanpakuto's blade grows in length and becomes completely white with a small white tassel hanging off the bottom.
Purify
He can bend light around others to heal them of minor wounds. He can also heal them of major wounds if he concentrates hard enough though it can drain his reiatsu quickly if he isn't careful.
Despair
He can channel light and reiatsu from himself and his zanpakuto into the blade of his zanpakuto, making it glow brightly and increasing its cutting power. He can then either just use the blade like it is or release it as a wave.
Bankai: Achieved
While in Bankai Yuki is in a full suit of armor and has increased defense, endurance, and strength.
Purify
He can heal others to a greater extent healing serious injuries and even purifying poisons. He can even regrow limbs if he concentrates for a long time though it drains his reiatsu rather quickly, but he can't revive the dead.
Despair
He can use a wave of pure light and reiatsu that can cause damage based on how much reiatsu is put into it. The wave now covers a wider area, but moves faster if released as a smaller version.
Extension Technique
He can focus light unto the end of his blade to cause it to extend at a fast pace. He can then keep the extension for a limited time to swing with greater range.
Surround
He can create a sphere of light around his opponent that slowly shrinks. Or alternately he can create a sphere of light around an ally that doesn't shrink and protects them.
Broken Blade Technique
In the event that the blade should break it doesn't break it shatters into tiny pieces, that turns all the pieces into light shards that fly towards his opponent(s) quickly. Yuki has no control over this ability and the shards move by themselves, but won't pursue the opponent real far.
Special Accessories:
Yuki wears the usual Shinigami uniform though his sleeves are longer than the normal almost covering his hands. The normally black uniform of a Shinigami was white with a black undershirt and his haori was black with the markings white. His Captain's haori is short sleeved so that his longer sleeved uniform is easily seen beneath it. Yuki also wears a simple black scarf around his neck. Yuki wears a silver ring on his right ring finger with the kanji for bravery engraved on it.
Skills/Abilities:
Vast Spiritual Power - Being a Captain he has Vast Spiritual Pressure that he keeps lowered unless fighting someone powerful.
Reiatsu Control/Sensing - He can control his reiatsu quite well and can even hide most of it he can also sense reiatsu quite well.
Somewhat Flexible - He is flexible, but not super flexible.
High Strength and Endurance - He has unusually high strength and endurance for the Fourth squad.
Lightning Fast Reflexes - Despite his skill in Shunpo he has lightning fast reflexes that allows him to react faster than most.
Photographic Memory/Observant - He possesses a photographic memory and is quite observant and knowledgeable.
Zanjutsu Expert - He is quite skilled in this field and can use two swords at once proficiently if he wants he is not a master in this field however.
Personality:
Yuki dislikes fighting if he doesn't have to. He is fearless and protective and doesn't mind taking a hit designated for a squad mate or friend. He is always kind and watches over his squad closely. However he is not above refusing treatment to people who verbally or physically abuse his Squad. He can be quite scary when he wants to be.
Biography/History:
Yuki was quickly enrolled in the academy when he arrived in Soul Society alone without a memory of anything except his name. He quickly flew to the top of his class excelling in kido and graduated in a little under three years at the top of his class. He was excepted into the fourth squad immediately for his zanpakuto's healing ability which was fine for him, he even ignored his zanpakuto's offensive ability. He quickly rose through the ranks until he became Lieutenant of the squad and began training for Bankai. Years went by with little to no progress and quickly he began to get restless, training more and more each day till he was training non stop, then he would literally fall over from exhaustion.
While on a mission his lack of rest caused him to fall in battle quickly when attacked by a hollow. The battle ended with his squad's third through seventh seats getting killed by hollows and he was wounded severely. While he laid there potentially bleeding to death his zanpakuto materialized in front of him and spoke to him. Whatever was said, when he was able to train again he did and was able to achieve Bankai shortly after, he then trained in using his zanpakuto's offensive capabilities. Shortly after his captain died of a sickness and he took over the squad since it was her final wish, he has remained such since then.
Theme Song:
Linkin Park - In The End
Breaking Benjamin - Until The End
Metallica - Unforgiven II
Powers:
Shunpo Expert - He can keep up with most Captains, but is by no means a master.
Kido Master - He is a master of all kido including Healing kido.
Bakudo
1. Sai (塞, Restrain)
4. Hainawa (這縄, Crawling Rope)
8. Seki (斥, Repulse)
9. Geki (撃, Strike)
9. Hōrin (Disintegrating Circle)
21. Sekienton (赤煙遁, Red Smoke Escape)
26. Kyakko (曲光, Curving Light)
30. Shitotsu Sansen (嘴突三閃, Beak-Piercing Triple Beam)
37. Tsuriboshi (吊星, Suspending Star)
39. Enkosen (円閘扇, Arc Shield)
58. Kakushitsuijaku (摑趾追雀, Summoning of the Tracking Sparrows)
61. Rikujōkōrō (六杖光牢, Six Rods Prison of Light)
62. Hyapporankan (百歩欄干, Hundred Steps Fence)
63. Sajo Sabaku (鎖条鎖縛, Locking Bondage Stripes)
73. Tozanshō (落下クリスタルマウンテン, Falling Mountain Crystal)
75. Gochūtekkan (五柱鉄貫, Quintet of 1 kan Iron Pillars)
77. Tenteikūra (天挺空羅, Heavenly Rickshaws in Silken Air)
81. Danku (斷空, Splitting Void)
99, Part 1. Kin (禁, Seal)
99, Part 2. Bankin (卍禁, Great seal)
Hado
1. Shō (衝, Thrust)
4. Byakurai (白雷, Pale Lightning)
11. Tsuzuri Raiden (製本雷, Bound Lightning)
31. Shakkahō (赤火砲, Shot of Red Fire)
33. Sōkatsui (蒼火墜, Blue Fire, Crash Down)
54. Haien (廃炎, Abolishing Flames)
58. Tenran (闐嵐, Orchid Sky)
63. Raikōhō (雷吼炮, Thunder Roar Cannon)
63. Sōren Sōkatsui (双蓮蒼火墜, Twin Lotus Blue Fire, Crash Down)
88. Hiryugekizokushintenraiho (飛竜撃賊震天雷砲, Flying Dragon-Striking Heaven-Shaking Thunder Cannon)
90. Kurohitsugi (黒棺, Black Coffin)
Chiyudo
Diagnostic:
#3. Naimenteki Joukei (Inner Sight) - A low level spell that allows Shinigami to check for internal bleeding by just hovering their hands over a body. Think small yearly checkup or physical exam.
#6. Naimenteki Bakuro (Inner Revelation) - More advanced then Joukei. This spell detects pain, bleeding, and infection. However it takes more drain out of the user. Think examination for breaks, fractures, or muscle tears.
#9. Naimenteki Hakke (Inner Divination) - The most developed spell of the set. This takes time and preparation to do. The Shinigami must have a scroll of paper ready. With one hand he will hover over the body, the other will print out a "scan" of their body. Incredibly skilled practitioners can even see future complications in the patients body along with the maladies already there. Think emergency scans for serious injuries.
Transportation:
#12. KyariSenshi (Carry Soldier) - The User creates a sort of stretcher out of floating white ribbons which wrap around the patient. It is useful for taking the injured out of battle in a pinch. The fabric is ultra durable and absorbs kido based attacks.
Treatment:
#5. Kai Kizu (Cut wound) - This kidou is used to heal cuts. Does absolutely nothing for internal. The more experienced the user, the faster this technique works.
#7. Seichuu no Netsu (Control of temperature) - This is mainly used for controlling the body temperature. It can be used to bring it up, or down. This is a very delicate process, and must be done slowly over time.
#16. Nenshou Tenti (Burning God) - This kidou creates a flow of reiatsu that first soothes the burn and then repairs them.
#17. Gyouko Tenti (Freezing God) - This kidou creates a flow of Reiatsu that first soothes the frost bite and then repairs it.
#23. Samasu (To Awaken) - This Kido channels a shock through the heart or brain with a small burst of Reitsu. Although a lower level Chiyudou, there have been cases where it has been able to bring back patients who have been 'dead' for up to five minutes. It's main use, however, is to wake someone from a kind of slumber, whether that be unconsciousness, sleep, shock, and by the hand of a skilled healer, even a coma.
#27. Chinseizai (Pain killer) - Pain. It can be a serious issue on the battle field, especially when a treatment is going to take a few minutes. Not good when a patient is thrashing about, and you are not strong enough to hold him or her down. This Kido channels the users Reitsu through the inflamed area, temporarily turning off nerve receptors. The negative to this, is that the treated area becomes numbed. Meaning the patient won't be able to move or feel it for a designated amount of time.
#33. Myouyaku (Miracle Cure) - This kido normally follows up Shinryou, above. The Reitsu sinks into an area infected by a poison, and generates powerful enzymes that help the body attack and dissolve harmful bacterias. After the job is done, the enzymes will be filtered and removed by the body.
#45. kiyasume kireme (Soothing Break) - This kido sinks Reitsu into a fractured or broken bone. It is a kido that takes time to work, even for more experienced users. It numbs the area, then begins to heal, for repairing of bones is a painful process. If a shinigami is not skilled with the technique, it can be seriously painful on the receivers side.
#48. kuttsukeru (To Attach) - This Kido is used to re-attach limbs, that have been separated from the body a short period ago. If this procedure is started fast enough, even detached limbs can be re-applied. This can be as simple as a tooth to a finger, to a leg or an arm. It works by reattaching nerve cells and blood vessels in the damage area, with the force of a binding sort of Reitsu.
#62. Fantomu Unten (Phantom Operation) - Reiatsu soaks into the body and phases through the skin. It is coined, "Phantom operation" by those who use it, as it allows one to bypass the layer of skin, blood, and sometimes even muscle, to get to the damaged area. This technique requires sound background knowledge and concentration, to mend tissue and blood vessels that would be impossible to get to in any other way.
#94. Zenchi (Complete Recovery) - This is by far the most difficult and envied healing technique. It deals with the spinal cord, and nerves system. After a long and grueling Reitsu treatment, which soothes and creates new nerve cells, a patient can be healed from almost any kind of paralysis or physically debilitating affliction.
Other Spells
Hakufuku (白伏, White Crawl) This technique muddles the consciousness of its target. Momo Hinamori uses this spell while imprisoned to knock out a guard and destroy everything within a certain radius of herself.
Kyōmon (鏡門, Mirror Door) Tōshirō Hitsugaya used this to seal Momo Hinamori's hospital room. It creates a glass-like barrier which is difficult to break from the outside, but quite simple to break from the inside.