Neco, Naze Boku no Sekai wo Daremo Oboeteinai no ka?, Rinne (Naze Boku no Sekai wo Daremo Oboeteinai no ka?), Reiren (Naze Boku no Sekai wo Daremo Oboeteinai no ka?), Kai (Naze Boku No Sekai Wo Daremo Oboeteinai No Ka?), Official Art, Novel Illustration