TV-Series
Description
Tiese Schtrinen, a sixth-class noble from Norlangarth North Empire in Underworld, enrolled at North Centoria's Sword Mastery Academy as her family's eldest daughter to improve their status. Ranking among the top twelve students due to Sacred Arts proficiency secured her a valet position, though higher-ranked nobles rejected her until Eugeo accepted her. She bore distinctive long red hair uncommon in her region, a slender frame, and a gentle demeanor, typically wearing the academy's grey uniform. Diligent, positive, and brave, she showed unwavering dedication to responsibilities and loved ones, developing deep admiration and romantic feelings for mentor Eugeo while forming a sisterly bond with roommate Ronye Arabel.

At the academy, Tiese witnessed elite noble Humbert Zizek mistreating valet Frenica Szeski. Confronting Humbert and Raios Antinous alongside Ronye provoked the nobles into exploiting legal loopholes to restrain and attempt assault as punishment for perceived disrespect. Eugeo and Kirito intervened by breaking the Taboo Index, resulting in their arrest. Tiese blamed herself for their plight and vowed to become an Integrity Knight to rescue them.

After Administrator's fall, Tiese joined the Human Guardian Army's supply unit against the Dark Territory invasion. Learning of Eugeo's death and Kirito's catatonia from Alice Synthesis Thirty overwhelmed her with grief. Touching Eugeo's shattered Blue Rose Sword released a residual memory of his consoling voice, renewing her resolve. Post-war, she advanced as an apprentice Integrity Knight designated Synthesis Thirty-Two, inheriting Eugeo's knight number and his sword. Renly Synthesis Twenty-Seven developed romantic feelings and proposed. Hesitant due to lingering attachment to Eugeo, she eventually accepted. To remain with the non-aging Renly, she used cryogenic stasis to freeze her physical age in her mid-twenties. She married Renly, had at least one child, and continued serving as an Integrity Knight.

Approximately fifty years later, to await Kirito and Alice's return, Tiese, Ronye, and Selka Zuberg entered suspended animation via stone-freezing spell in Central Cathedral. After two centuries, Kirito and Alice awakened them. In the Unital Ring era, Tiese encountered descendant Stika Schtrinen, startled by her resemblance to Eugeo.

Tiese specialized in single-handed straight sword techniques, often coordinating seamlessly with Ronye. Partnered with frost dragon Frostbloom as an apprentice knight, she participated in major conflicts including suppressing a rebellion by the Four Empires' leaders, confronting the Norlangarth Emperor alongside Ronye.