Red Devil Vampire Crabs are decapod crustaceans part of Brachyura (from the Greek βραχύς = short, οὐρά = tail/abdomen).

The species is named after the Rolf C. Hagen Group, which supported work by Christian Lukhaup and Christoph D. Schubart, two of the authors of the describing article.

The common name was given as a marketing move in order to attract more attention to the crab from buyers and keepers.

Geosesarma hagen is a species of small land-living crabs only found in Java, Indonesia.

The crabs prefer a humid environment with elements from both terrestrial and freshwater aquatic habitats.

Young Red Devil crabs spend most of their time in the water as a way to avoid predators.

They are used to living in warm humid conditions and their preferred temperature ranges from 24-28 degrees Celsius (75-82 F).

There are many species of Geosesarma crabs living in the same natural habitat in Java, and they can all be easily identified by their bright and unusual colors.

They undergo molting in order to grow and recover lost legs and limbs within a few months of losing them.

Red Devil Crabs are nocturnal and spend most of their life hidden from the light in order to avoid predation.

The Red Devils are omnivores (though they show a preference for carnivorous prey), and their diet ranges from small detritus and dead plants to fruit flies, woodlice and other bugs.

Two new species of Geosesarma de Man, 1892 (crustacea: Brachyura: Sesarmidae) from Palawan, the Philippines.