(kä - rü - shé) n. Death from overwork. [<Jap.]
When the High Lords gathered to invade Core Earth, they realized that they would have to work closer together than ever before. As usual, the Pharoh Mobius did not play well with others. Ultherion and Malreaux worked together out of friendship. Kranod out of desperate need. But The Gaunt Man and 3327 had other reasons. Both being "students of human nature", they new it was wise to keep their friends close, and their enemies even closer, and so chose invasion sites that would keep the other in close watch.
But early on in the War, the Gaunt Man found himself trapped in the Heart of Coyote, while the invasion went on without him. Upon his escape, he had a great deal to catch up on. Learning of 3327's treachery in the Waiting Village uprisings, the Gaunt Man decided that something had to be done, and so personally crafted a new Horror, to prey exclusively upon the corporate reality of Nippon. But unlike his foe, who was often driven by his Darkness Device and the Law of Profit to take action before it is prudent, the Gaunt Man was willing to take time with his vengeance.
Knowing that even the corrupted soul of a Nippon inhabitant is not to be trusted, the Gaunt Man instead fashions this horror from Core Earth businessmen, promising them the world for one measly soul. The Karoshi enters the workforce at the bottom, usually by killing and assuming the identity of a lowly mailroom clerk or data entry specialist since Nippon corporations are wary of hiring "outsiders", no matter what their qualifications. There it begins a campaign of economic terror against it's employer - important packages are misrouted, trash is shipped without going throguh a shredder, but never in the Karoshi's area, using it's innate abilities to cover it's tracks. The creature quickly rises through the ranks, it's supernatural stamina allowing it to work longer hours than it's coworkers, and it's Occult knowledge granting it access to information that mere Business can not - stock reversals no one had anticipated but the Karoshi, mistresses and worse economic improprieties brought to the attention of the appropriate parties, and so on. In the cutthroat world of corporate politics, a creature born of fear, mistrust, and loathing is right at home.
But in the end, the Karoshi lacks a real "head for numbers", and will never be able to rise to a management position. So it does not try. It is content to be the best it can in it's position, always turning in perfect work, never complaining about it's boss' demands, and forcing it's co-workers to try even harder to keep up with it. As is the case with much of the Occult, there is even a short term gain for the corporation as performance increases in the Karoshi's section. But as is well known in Orrorsh, the flesh is weak, and soonor or later they can not keep up, taking their own lives and often the lives of others as the price of their failure. Madness and Death surround it, but the Karoshi continues to do it's job. Perfectly. Forever.