Tia serves as an information broker within the ARKS organization, operating alongside her twin sister Pati from their station in the Shopping Plaza's Monument Square. Together, they issue Client Orders to fellow ARKS operatives, including missions like "I Want Your Help!" demanding an S Rank clear of Amduskia's Dragon Altar Exploration, and "Take My Cute Sister on a Journey!" requiring an S Rank clear of Wopal's Coastal Region Ecological Survey with Tia as the sole partner. Successful completion earns monetary rewards and unique items such as their Partner Card.

Frequently accompanying Pati during story events, Tia acts as a moderating counterbalance to her sister’s impulsiveness. She routinely apologizes for Pati’s unrestrained remarks, reflecting her own reserved and conscientious demeanor. Her investigative skills emerge during incidents like Ash’s rumor targeting, where she advises caution and helps trace the source. Tia further aids in uncovering suppressed historical truths, joining Pati to interview ARKS leaders Regius and Huey about inconsistencies in records of the Dark Falz assault a decade prior.

Tia demonstrates deep concern for ARKS members during crises. She alerts Ash to Echo’s disappearance on Naverius and voices worry for her safety. When Falspawn attack the medical center, Tia helps defend patients and Io, reacting with visible shock to Io’s insistence on rescuing trapped individuals. In broader conflicts, she supports Ash’s efforts to unite ARKS against threats, collaborating with Quna to hack the fleet’s announcement system and broadcast his plea for aid.

Her deployments span Oracle Fleet operations, including reconnaissance, intelligence gathering, and combat support alongside Pati on Wopal’s Coast and Seabed, Amduskia’s Dragon Altar, and Naverius’ Forest.