Tiese Shtolienen, eldest daughter of a sixth-class noble family within the Human Empire of Underworld, dedicates herself to the Sword Mastery Academy in North Centoria to elevate her family's status. Her exceptional Sacred Arts proficiency places her among the year's top twelve trainees, securing her the role of valet to elite disciple Eugeo. Slender with long, vibrant red hair—a rarity in Norlangarth North Empire—she embodies diligence, positivity, and a strong work ethic. Eugeo recognizes her lively spirit and high motivation. She deeply respects her father's teachings on noble responsibilities towards lower classes.

At the academy, Tiese forms a close friendship with fellow valet Ronye Arabel and develops deep feelings for Eugeo, leading her to propose marriage should he gain lifelong nobility at the Four Empires Unity Tournament. Her resolve is tested when higher-ranked nobles Raios Antinous and Humbert Zizek exploit legal loopholes to detain her and Ronye under false pretenses, intending assault. Though Eugeo and Kirito intervene, the ordeal leaves a profound mark. Tiese later grapples with guilt over Eugeo's arrest after he violates the Taboo Index protecting her.

Following the Axiom Church's collapse, Tiese volunteers for the Human Guardian Army supply unit to defend against the Dark Territory invasion. Learning of Eugeo's death and Kirito's catatonic state shatters her. Solace comes when touching fragments of Eugeo's Blue Rose Sword allows her to hear his final message, restoring her resolve.

Non-canonical media like *Alicization Lycoris* expands her academy experiences, depicting participation in activities like beast extermination alongside Eugeo, Kirito, and Ronye, strengthening their bonds. It also portrays her determination to become an Integrity Knight to rescue Eugeo after his arrest. Her name reflects her parents' wishes for her to embody energy, helpfulness, and military talent.