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Angelina Kudou Shields (アンジェリーナ・クドウ・シールズ) is the Head-Captain of the USNA's Magician Unit "Stars". She holds the rank of Major.  Her nickname is "Lina", rather than "Angie".  Her nickname in childhood was "Angie", while she calls herself "Lina". 
Appearance and Personality
Lina is a beautiful girl whose beauty is no less than that of Shiba Miyuki's. She is a young girl with blond hair and blue eyes. Her two wavy tresses on the sides of her head are secured by ribbons and, if released, would likely trail to waist length.  When the title of "Queen" morphed into "Twin Beauties", it was used to describe Lina and Miyuki for being the most beautiful girls of First High by the female and upperclassmen. 
For a high school freshman, her mature gaze didn't go very well with her childish hair style, but it perfectly coincided with the perfect blend of shock and beauty, and with a degree of familiarity to go along with it. 
Upon enrolling at First High, she shows a polite and friendly personality. However, she gets easily flustered and falters when asked about inquisitive questions, which makes her inept in information gathering missions according to her own words. She had some misgivings about Japanese fashion, as she wore a completely outdated outfit during her first encounter with Tatsuya and co, prompting her subordinate Sylvia to scold her. She also has a competitive side, which usually surfaces when facing against Miyuki.
As a soldier, Lina takes great pride in her position as Sirius and follows her orders to the letter (even orders such as executing the deserters from the USNA military, despite being acquainted with some of them), showing a great sense of responsibility. However, she dislikes such missions and she even vomited after her first few "hunt and execute missions". According to Tatsuya, Lina doesn't have the necessary mentality to be a soldier, as she is too gentle.She also appears to believe that it's the duty of the Magicians to serve their country and that she herself was the only one who could bear heavy responsibilities as one of the strongest magicians alive, showing a somewhat simplistic way of thinking. However, her encounter with the Shiba siblings made her to start questioning those beliefs and realize that she could (and can) choose a different path in life.
Over the course of her stay in Japan, Lina is shown to have developed feelings for Tatsuya, something she instinctively knows but refuses to admit.
Lina is someone with an incredible voice who has talent not inferior to that of a professional singer. 
She acted as a foreign exchange student from USNA who attended First High School in 2095 while undercover, meanwhile Kitayama Shizuku went to study in USNA city of Berkeley, California.  She was made a temporary officer of the First High School Student Council. 
- Main Article: Sirius
She joined Stars three years ago, but she only has had a military career of one and a half years, even after she took the position of High Commander of Stars.
Lina's instructor during her time in the candidate unit known as "Starlight", was Second-Lieutenant Angelina Mizar. 
With the title of "Sirius" bestowed upon her, Lina is given the honor and status of being the most powerful combat Magician in the USNA military. Only those who have defeated the previous "Sirius" can earn this title. She relies on her superior speed in magic activation and physical movement to overwhelm her opponents in a battle. Furthermore, unlike many magicians, she is not above using assorted weapons, from knives to an automatic pistol equipped with a silencer to supplement her impressive hand-to-hand combat skills and magic abilities. Lina also shows resistance to Parasite and Mental Interference Magic.
Lina is not only skilled as a Magician, but also as a physical combatant. Tatsuya notes that while Lina's hand-to-hand skills weren't on his level (i.e. master level), they were more than enough to be classified as first-class. Lina appears to be highly well-trained and boasts incredibly fast physical movements, which she uses in conjunction with her magic to take opponents down.
Purely in terms of magic, despite her ability to use Strategic-Class Magic (which by definition is large scale, wide-area magic), Lina naturally specializes in high speed, small-scale, high-impact magic. As such, her invocation speed is blindingly fast, even faster than Miyuki's, whose processing speed was so fast that the school equipment couldn't keep up and accurately measure it. Lina's invocation speed is presumed to be the fastest of any character introduced so far. Both the power and reach of Lina's Zone Interference appear to lose out to Miyuki's, however, her magic abilities are nevertheless among the highest of caliber among Magicians in the world.
A specialized CAD that has several Movement-Type spells programmed into it. Throwing the knife activates the magic to speed up the knife and change its direction.
A medium-sized automatic pistol with a silencer that Lina usually uses to execute deserters. She applies Data Fortification on the bullet to pierce through the passive Data Fortification that all Magicians employ as a defense.
Brionac is a special weapon developed by the USNA to allow for the tactical use of the Strategic-Class Magic Heavy Metal Burst, giving Lina the ability to use a focused, small-scale version of Heavy Metal Burst in normal combat situations. Brionac forms a barrier to contain the shock wave released from the transformation of plasma and prevent the plasma from causing extraneous damage to the surroundings such as a populated city.
Imitating the spiritual weapon, Brionac, which was said to be a spear of light that could pierce through anything, its operation system is based on the classified Free After Execution (FAE) theory. The theory states that there is a small gap in time between the invocation of magic and manifestation of the effects. Brionac manages to control Lina's magic output by taking advantage of the time gap, which is impossible for a human to use or take advantage of naturally.