Created as a True Werewolf by Beast King Mekongawa, Lupusregina Beta serves within the Pleiades Six Stars, Nazarick's elite battle maid squad defending the Great Tomb. Her core purpose is to distract intruders breaching lower floors, buying time for guild members preparing their final stand in the throne room.

She possesses brown skin, red hair in two long braids, and an athletic physique. Her distinctive maid uniform features short sleeves, long black gloves, a high-slit skirt revealing thigh-high white stockings, and a garter belt omitted in anime adaptations. She carries a large black-and-silver scepter across her back.

Outwardly cheerful, sociable, and friendly towards humans, Lupusregina frequently engages in lewd jokes and teasing, especially with Carne Village's Enri Emmot. This demeanor masks a brutal, cunning, and sadistic core. She delights in startling others using 'Complete Invisibility' and finds amusement in observing distress. Her cruelty intensifies during full moons. Despite this, Homunculus Maids consider her the friendliest Pleiades member.

Assigned by Ainz Ooal Gown to monitor Carne Village, she protected Enri Emmot, Nfirea Bareare, Lizzie Bareare, and later Nemu Emmot. She aided village reconstruction with stone golems and delivered alchemical supplies but refused chores, citing dedication solely to the "Supreme Beings." When Enri declined Ainz's aid against threats, Lupusregina showed visible disappointment. After Ainz reprimanded her for carelessness in this duty, she advised Enri on leadership responsibilities, subtly manipulating events to ensure the village's dependence on Nazarick. She later saved Nfirea from a Giant Troll.

During Prince Barbro's assault on Carne Village, she observed invisibly. Intercepting his retreat on Katze Plains afterward, she summoned thirty Redcap Goblins to slaughter his soldiers and personally tortured the prince for thirty minutes until death.

She participated in Nazarick's major operations: posing as a subordinate of the demon Jaldabaoth (Demiurge) alongside Solution Epsilon and Entoma Vasilissa Zeta during the Men in the Kingdom arc, and repelling the Dragon Hunt worker group during the Invaders of the Large Tomb incident.

In the Paladin of the Holy Kingdom arc, she attended high-level strategy meetings with Ainz, Albedo, and Demiurge. When Floor Guardians demanded she forcibly lift Ainz's bowed head, she refused out of deference, later whispering in amazement at the proceedings.

Following Nazarick's transfer to the New World in the "Mass for the Dead" storyline, Lupusregina was among NPCs killed during the transition. Revived by Momonga, she suffered severe level depletion. Later, during Crack monitoring duty on the 6th Floor, she neglected to report increased Chaos Beast numbers and undead guardian casualties. Ainz reprimanded her harshly for endangering Nazarick and removed her from duty. Guided by Cocytus and the protagonist homunculus, she learned the principles of "Hō-Ren-Sō" (report, contact, consultation) to rectify her failures. After demonstrating understanding to Albedo, she assumed messenger duties from Entoma, seeking to restore her standing.

Her combat capabilities include 100 total levels distributed across racial classes (True Werewolf) and job classes (Cleric, Battle Cleric, Mage, Barbarian). She wields diverse spells: healing magic, offensive fire spells (Fireball, Vermillion Nova), invisibility, teleportation, and high-tier attacks (Nuclear Blast, Meteor Fall). Her equipment includes a Divine-class maid outfit and a crosier.

Lupusregina developed genuine respect for Enri Emmot's leadership and resilience, a rare acknowledgment from a Nazarick NPC toward a human. Ainz later regretted not selecting her as his adventurer companion instead of Narberal Gamma, recognizing her superior aptitude for interacting with humans despite her underlying sadism.