After Walpurgis, Rimuru's territory expands to cover the entire Jura Forest. It was expected that this would result in a flood of greetings from races with whom he had no contact with. Also, while considering the construction of a highway, Rimuru learned that the road would lead to a mountain ruled by the Tengu tribe, so he decides to send Benimaru as an emissary. With diplomatic issues piling up, Rimuru came up with the idea of holding a Founder's Festival as a means of diplomacy and to attract new residents.