Shiyo Kohara, a spirited university student and devoted friend of Chiko Shinmoto, balances her supportive nature with an infectious energy. She sports wavy, shoulder-length light-green hair styled with bangs swept to the right, complemented by emerald-green eyes and a subtle mole beneath her left lip. Her surname, Kohara (小原), merges "small" and "field," reflecting a grounded simplicity.

Shiyo often steps in to help Chiko calculate the minimum attendance required to avoid academic setbacks, frequently expressing playful astonishment at their campus encounters due to Chiko’s sporadic class habits. In contrast, Shiyo adheres to a steadier routine. Her personal life revolves around a boyfriend deeply engrossed in online gaming, leading their relationship to thrive through virtual dates. They reunite in person twice yearly, prioritizing shared visits to Comiket.

Within the series, her presence weaves responsibility with humor, anchored by the nickname "Shiyo-tan"—a term of endearment from Chiko that encapsulates their lighthearted camaraderie.