In a prosperous city that has survived in its current location longer than three centuries, rent a hotel room as close to the city-center as possible. If you absolutely must have this Holder's object, then you will have already asked the hotel manager to see the one who calls himself "The Holder of Mortality", and if you have in fact said this, then I sincerely hope that you succeed, for failure to obtain this object will result in consequences that would drive even some Holders to madness. Remain in this room for three days without making verbal contact with any resident in the area and without even thinking about leaving, no matter how many lonely corpses arrive to casually gnaw your sensitive skin. If at any moment, a cry for mercy exits your lips while in your voluntary prison, you may do whatever it is that you wish to thwart your imminent kidnapping and sadistic torture. Your cover will have been blown at this point, and the starving minions soon to be released from your own subconscious will hunt your marked, crave-able flesh for as long as you roam your world.
If, by some miracle of human ingenuity, you manage to stay in this room for three days without losing your sanity, congratulations, now get the hell out of there, you have work to do.
Many changes have taken place in the outside world during your time in the room; you'll see what I mean once you get this far. Pay attention to the behavior of the people around you; for example, you will notice that it seems as though everybody is eating each other. I wouldn't spend too much of my time observing my peers, though.
Just keep walking; your destination is the absolute center of the old city. Hopefully the sun shines during your journey; otherwise, watch your step: the Holder you are about to meet has many fingers, and he just hates it when one gets stepped on.
The center of the city will be distinguishable by two things: firstly, a bird's nest in a skinny, white tree; and secondly, a horrendously massive and odorous fleshy mass writhing on the ground. Do not be intimidated by his stature or stench, as the slightest doubt or fear in your mind is all he needs to discover your presence - and your motive.
The remaining steps should be easy if you have managed to make it this far without an ounce of internal fear; simply creep up to the thrashing mass as silently as possible and push something sharp into his soft underbelly.
If your have not wounded him, then your existence in That Place will be yet another deterrent to future Seekers. If done correctly, however, a pale, yellow liquid should come out of from the wound and you will be largely out of danger as soon as your victim has deflated and shriveled to an almost human-like shape.
He is now totally harmless (though still, I would not step on his fingers) and it should be safe to ask him "Will He ever die?" You must listen carefully to his response as his lips will be covered by layers of shriveled skin. His answer will be brief; when he has finished, feel free to search through the Holder's slime for his object. My suggestion would be to close your mouth during your search, as well as any other orifice in your body. You wouldn't want it inside of you.
The parasite is Object 169 of 538. Keep it away from your stomach.