Angelene is a Roman Catholic Church nun serving in the paramilitary Agnese Forces under her friend Agnese Sanctis. Abandoned by her parents in Milan after moving from France (with her specific birthplace unclear), the Church took her in. There, she met and formed close bonds with Lucia and Agnese Sanctis. This difficult past fostered her hardworking and loyal nature despite pronounced timidity.

She possesses a small stature, freckles, and long honey-colored hair usually worn in twin braids. Her loose-fitting nun habit often covers her hands and feet. A distinctive metal waist belt holds containers for coin bags used in her magic. Her exact age is unspecified, though she appears younger than Agnese.

Angelene exhibits significant shyness, frequently adopting defensive postures like slouching or holding her arms close. She struggles to act independently on her beliefs, making her easily swayed by stronger personalities like Lucia—evidenced when she attacked Kamijou Touma after he touched Lucia. Despite this, she displays childlike traits: tearing up easily, trusting quickly (as when rescued by Touma and Orsola Aquinas), and having a strong sweet tooth, especially for hot butter cocoa chocolate. Her gluttony rivals Index's, leading to conflicts over food. During arguments, she habitually uses distractions like flipping Lucia's skirt. Angelene also expresses envy towards larger-breasted women like Orsola and Lucia, resenting Lucia's dismissive comments. While faithful, she is less extreme than Lucia or Agnese. As a nun-in-training, Lucia frequently corrects her etiquette or work lapses. However, she shows seriousness in crises and compassion for enemies, like expressing concern over her coin bags' weight before battle. She deeply admires Agnese, striving to follow orders precisely and undertaking significant risks for her, entering battles despite fear or attempting rescues against overwhelming odds.

Her magic centers on coin bags stored in her belt containers, referenced as the "Coin Bags of St. Matthew" from Matthew's Gospel, functioning as projectile weapons.

Angelene first appears alongside Lucia during the Orsola Aquinas Rescue Arc, attempting to capture Tatemiya Saiji. After Touma angers Lucia, Angelene reluctantly helps attack Index but retreats following Spell Intercept. Later, captured during Agnese Sanctis's protection detail after Touma defeats Agnese, she and Lucia are forced into labor on the Queen's Fleet in the La Regina del Mare Adriatico Arc, wearing magic-suppressing robes. A failed escape precedes rescue by Touma and Orsola; Touma's Imagine Breaker accidentally destroys the robes, freeing them but causing disrobement. Angelene then aids the Amakusa-Style Remix of Church in planning Agnese's rescue, demonstrating resolve to save her leader despite fighting former comrades. She sustains injuries protecting an ally during the assault. Post-war, Agnese Forces relocate to the Anglican Church Women's Dormitory under Necessarius, with Angelene representing Roman Catholicism in England. During the Academy City Invasion Arc, she advocates adopting a washing machine due to laundry strain. Later, she confirms Kanzaki Kaori's lack of underwear under a yukata during a washing machine test. At the Anglican Church–Russian Orthodox Church Prewar Conference, she argues with Lucia about breast size envy.

Following improved inter-church relations, Agnese Forces return to Roman Catholic authority, a transition minimally affecting Angelene's personality.