An original character by oso (toolate) that is a personification of the 'Hypholoma fasciculare' species of mushroom, also known as the sulfur tuft or clustered woodlover.
Their names are listed on oso's website and in his artbook as "Nigagori I-V Marron" (苦栗・Ⅰ(~Ⅴ)・マロン.) They are nicknamed the "Bitter Marrons."