Black Plague releases black clouds around the user that infect nearby targets, causing them to take damage over time and periodically release more black clouds, dealing more damage and infecting more targets. Infected non-boss targets have a small chance to be instantly defeated whenever taking damage from this weapon.
"Black Plague" is the other name for the "Black Death", a pandemic of flea-infested rat-spread bubonic plague that ravaged its way throughout Europe in the 14th Century, causing one of the highest losses of human life from a plague in recorded history. The Black Plague was parodied in Nanashi Mumei's Dan Dan Don Don animated video, where she unleashes Hakos Baelz - a rat - to infect a village of owls with a deadly illness. [1]