Ghorpm: EDIT: new one:
OK, so I'm a guardian and blah, blah, blah, boring my job sucks. I'm ordered to guard an entrance to a chamber where an important meeting is being held and politics. But it didn't turned to be boring after all... assassins! I jumped into action killed a bad guy but then I got poisoned and paralyzed. I'm in a hospital now. It turns out that the poison is very nasty. It will mutate me, I'll get stronger because of it but eventually I may lose control over myself, so I should better find a cure.
How is that NOT [url=http://en.wikipedia.org/wiki/Blood_Omen:_Legacy_of_Kain]Blood Omen: Legacy of Kain[/url]
During a journey, the human nobleman Kain is ambushed and killed by a band of assassins.[15] Mortanius offers him the chance to exact revenge—Kain assents, heedless of the cost, and awakes as a vampire.[19] Once he kills his attackers, Mortanius tells him that, while they were the instruments of his death, they were not the ultimate cause. In search of the truth, and a cure to his vampiric curse...
Vampire=mutant and vampiric curse could be poison :D