Oblivion is what happens when any human dies. It is the end and absolutely nothing is left of you except your cold-dead body which will also eventually disappear. It is best summarized as "nothingness" or "non-existence". Since the "soul" is a creative human construction invented by various cultures, we can be fairly confident it doesn't exist. You aren't going to heaven nor will you reincarnate, join universal consciousness or exist in any form at all. Your existence is over. You are kaput. Its disappointing news for some...and welcome by those who realize eternal existence would be grotesque in any form. Eternal oblivion is extremely difficult for many people to accept as we have been culturally conditioned to believe this life is just the beginning. Yet there is not even the slightest shred of evidence this is the case except for "near-death experiences" which are easily explained as physiological and psychological reactions. One advantage to accepting that once you die, that's it...is you can entirely focus on this life...the only one you likely have and leave valuable footprints. Because once youre gone all that is left is a decomposing corpse and the footprints you leave.
When the brain dies so does conciousness. There is no conceivable way that conciousness may survive after brain death. Some superstitious people have various magical theories as to how conciousness might continue however they are all without evidence and totally bananas when viewed rationally.
What is left of you
The only thing left of you is the decomposition of your body if you haven't been created or destroyed by force. Amongst the first cells to decompose are cells of the nervous system as they rely on oxygen more than other cells. As the circulation system has stopped functioning these cells have very limited access to oxygen. Brain cells can die within three minutes of death. The brain if left in tact will break down in a form similar to some other organs. Through no concievable mechanism can consciousness survive when your brain is liquidised or rests in ashes.
Resucitation and oblivion
That humans can be legally dead for a few minutes and resucitate or more importantly if humans can be revived through some yet discovered technology (freezing the body for example) what does that say about the time between your death and resucitation? Is it eternal oblivion or is it more analogous to a computer when it is shut off with no activity at all? Eternal oblivion would suggest once it begins it is forever though it can be argued that only really happens once the brain is completely beyond any possible recessitation. Is it temporary oblivion in between?
It is common to think of oblivion as some shadowy existence or blackness or emptiness. This is a misconception of oblivion. Oblivion is nothing. It cannot be black or empty because it's a lack of anything. It is no different to before you were born. There was absolutely nothing of you, nowhere in any way. The same is for death. It is non-existence.
Decomposition of the body
The human body will decompose over a period ranging from days to centuries depending on how well the body is shielded from humidity, wind, water and organic life. A body may be preserved through mumification, freezing, embalming or other natural and unatural preservation. It is currently beyond our technology to preserve and recesiate a body that has undergone rigormortis and or brain death.
Eventually all organic life will decompose and the matter that once made up the body will disperse into soil, air, bodies of water as well as beyond earth's atmosphere. It should be noted that human bodies are always shedding mater and that such shedded mater is effectively no different to the matter that disperses after decomposition. A human typically sheds skin cells equal to twice their body mass over a life span of seventy years.
Once the body has fully decomposed a person can be considered totally obliterated (both consciousness at brain death and later the body). All that remains are footprints (physical and recorded) and memories in living people. Foot prints should not be thought of as a substitute for you, they are just footprints, memories, feelings in others and objects that remind others of you and what you did. Your actions, values and ideas can possibly disseminate and impact the world for many generations after you die as well as objects you have constructed or used. However those are physical and conceptual artifacts, not you. Eventually these will also disappears until absolutely nothing is left of a person.
It is very unlikely that records of human existence can survive beyond a galactic catastrophic events meaning if there is some universe ending event (heat death, big crunch etc) or all traces of conscious life disappear then that would be eternal oblivion for humanity. There won't even be any footprints of our existence at all. And in any case...no one would be around to even care.