Hemotropic Butterflies have a red body and bright red wings. The tips of their wings are a darker shade of red.
Hemotropic Butterflies can detect the scent of blood from a good distance. The more blood there is, the more butterflies gather around the victim. However, like ordinary butterflies, they can also feed on nectars.
Hunter Exam arc
Attracted to the scent of Gon's blood, a few Hemotropic butterflies feed off the open sores on Gon's hands. This inspires Gon to use one to locate the wounded Hisoka.