Kasenjiki fervently supports Yuya Niyodo of the idol duo ZINGS, channeling her dedication through vibrant green hair and a striking ensemble: a red happi coat, navy blue pants, white shoes, and a headband studded with glowing lightsticks. Her surname, translating to "riverbed," mirrors her stabilizing influence within the fanbase, where she cultivates camaraderie and guides newcomers with warmth.

She forms a trio of Niyodo devotees alongside Shigutaro and Tsugiko, rallying at live events to celebrate his dual personas—"God Mode" during electrifying performances and "Cold Mode" for his typically aloof stage presence. While official media avoids explicit backstory, her proactive engagement and kindness underscore her role as a linchpin of fan culture.

A subtle contradiction in source materials casts ambiguity on her gender, with one reference labeling her male against others that consistently use female pronouns. The anime adaptation amplifies her group’s presence early on, showcasing their dynamic without deviating from her established traits as an enthusiastic, community-driven supporter.