Behaviorally, Kotengu exhibits savage and violent tendencies. Typically solitary, they may cooperate with others, including other yōkai, to achieve goals. Their actions involve hoarding trinkets or valuable magical items, committing abduction, torture, murder, and desecrating sacred sites. They specifically target monks and nuns, relish causing sacrilege, and engage in cruel games like dropping people from heights or tying children to treetops. A recurring weakness is their overconfidence, which often leads to them being tricked into trading powerful items or information for worthless objects.

Within the narrative, Kotengu allies with Shimon Nagareyama, one of the Eight Guardians. The specific circumstances, duration, or nature of this relationship remain undetailed. Kotengu's role in pivotal story events, character development across any media, fate, further motivations, or impact on the overarching plot is not detailed.