Sydonay holds a commanding position within Bal Masqué’s Crimson Denizens as one of the Trinity leaders, alongside Hecate and Bel-Peol. A strategic authority, he directs pivotal operations such as synchronizing Hecate with the Reiji Maigo and initiating the Fountain of Existence. His protective instincts toward Hecate manifest through decisive actions, including rescuing her from Alastor’s flames during the failed synchronization and prioritizing her safety amid crises. Though respectful of her autonomy, he monitors her emotional state during disturbances at Seireiden and facilitates her connection to Yūji Sakai’s memories, temporarily alleviating her existential void through their synchronization. When the process collapses, he reassures her and ensures her escape.

Beyond his stern leadership, non-canon portrayals inject levity into his dynamic with Hecate, such as her chiding him to quit smoking and improve his habits—a contrast to his usual gravitas. His loyalty remains unwaveringly aligned with Bal Masqué’s objectives, including activating the Great Binding Chain and advancing their deity’s summoning, the Snake of the Festival. While his origins remain undisclosed, his identity is defined by guardianship over Hecate, adherence to the Trinity’s collective agenda, and calculated execution of the organization’s grand designs.