Master Joe

Roughly the size of a person, Master Joe hid beneath a hooded top marked with the word Joe and wore a rigid, mask-like face. A single eye and a mouth sat on that face, aligned so that together they traced the outline of a keyhole. Behind him trailed a long black tail capped with three rings that mimicked the grip of a key. Keys defined the rest of him as well, since a skull-shaped one hung from a chain at his neck, more dangled in bunches from his waist, and black shorts with running shoes rounded out the look.

For all his timidity, Master Joe held a streak of spite and, in his last moments, a measure of self-sacrifice. Fully aware of the danger it posed to everyone around him, he still made the choice to set Evil Natural Water loose.

During the assault on the Monster Association Headquarters, Master Joe stood watch over the vault beside a cluster of other monsters. When Atomic Samurai's students and the survivors of Narinki's Private Squad wiped out that guard, he scrambled to crack open a massive safe. A shot from Tongara struck him, yet he managed to breach the containment tank holding Evil Natural Water and release it into the fray. He could reshape his own arm into a working key, and it was this trick he used to open the sealed room. The unleashed chaos proved his undoing, as Mad Doctor Fish killed him amid the confusion.