Blade of Jagged Plague(3.5e Equipment)
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One wizard, one vampire, this princess of horror has declared a war against a continent. All its kingdoms, and all its churches made an alliance to defeat her. They managed to defeat her, but their loss was a third of all living in it. And she escaped... One of vampire goddess Shilah's special artifact that she has forged in the time between her life of humanity and her life of deity, this blade has been known to cause a powerful plague that drives all living creature away from it.
This is a +5 Wounding Bastard Sword. Its blade is actually serrated with a group of smaller, randomly shaped protrusions, making its wound as if by a saw. It seems to be made out of some sort of an alloy containing adamantine and is almost indestructible, and the blade can overcome 10 points of hardness. The blade has some part of it covered in mucus at all times, giving it a disgusting glitter. This sword releases a sickening stench that is only sealed when it is sealed in its blood-red sheath.
When the user hits its target with this blade, the user may choose to activate its special power. The user rolls a d20 and adds his/her constitution modifier. Then, the user chooses 2 diseases (here is a list of homebrew diseases) with its infection DC lower than the result of the roll. The target becomes target of infection by both diseases. The user can choose one of the disease to either take effect immediately (no incubation period), or raise the save DC by half of the user's constitution score. If the user rolls a natural 20 with the attack (followed by a successful roll to confirm the critical hit), the user can also infect the target with poison, either as the poison spell or by any other specific type of poison (see list of poisons)with save DC equal to or less than the user's constitution roll. If the target makes the save against disease made immediate, the target becomes immune to that specific disease and cannot be infected by it.
 The Plague
Once per day, the user must roll a fortitude save. If the user rolls a 1 (and roll again to confirm with a 1 or a 2), the blade unleashes a plague onto the user. This plague is a special disease with no incubation period, and is contagious by contact. 2 years after the infection, the subject must roll a fortitude save against a DC 30. A failed roll instantly slays the subject, and even with a save the subject permanently looses 1d10 Constitution. The subject cannot recover naturally and continue to suffer from its effect weekly until the subject dies.
Curing one subject of this plague with the Heal skill is 45, and can be attempted at a same subject only once per day. Remove Disease spell cannot remove this plague, but Heal spell can be directed at the plague, with a DC of 30 to remove it (but not recover lost Constitution points). Wish and Miracle can both remove the plague from an individual and restore Constitution with no cost, but removing the plague from more than one requires 100XP for each person more than one.
Creatures without Constitution scores don't suffer from this effect but they still catch it. From the moment they touch an infected individual, they are considered infected. Thus anyone touching such creature also becomes subject of the plague. After a week from being infected, such creature will no longer be infected as the plague is shrugged off its surface.