Kappa, a mischievous monster found in Japanese folklore, supposedly lives in a stream or pond, and has webbed hands and feet so that it's good at swimming. Human hands also have an interdigital web in the early embryo, but it disappears by apoptotic programmed cell death like a tadpole's tail. The intracellular signaling pathway that triggers apoptosis has been studied well; the signal flows down the 'cascade' that consists of multiple caspases (Cysteine-ASPartic proteASE) such as caspase 9 or 3 encoded by CASP9 or CASP3, respectively. This poor Kappa in this drawing has been saturated with the water flowing down the caspase cascade, and its vaunted web is in danger of disappearing by apoptosis.
Shoki (Zhong Kui in Chinese), derived from Chinese Taoism, is a god for warding off diseases. According to a legend, one night when Emperor Genso (Xuanzong) of the Tang Dynasty had a high fever, Shoki appeared to him in a dream, killed a monster, and saved the Emperor at last. In tribute to the legend, Shoki has been worshipped as a god who protects people from illness for hundreds of years in China and Japan. The role of Shoki in the legend is that of the immune system itself. In this drawing, Shoki holds a sasumata (spear fork) with an IgG-like spearhead in the right hand and wears a cloth with a crest of IgM and a pattern of a dendritic cell; they are weapons of mammalian adaptive immunity. In contrast, his left hand contains a monster (pathogen) by melanization, which is one of the weapons of the innate immunity of insects. We thank Prof. Hirotaka Kanuka's lab (The Jikei University School of Medicine) for their valuable suggestions for our drawing.