In this world, the life & death cycle has been interrupted for almost a century. People don’t die due to natural causes, and don’t age once they reach maturity. Horribly, those who are affected by certain poisons or come down with crippling diseases also don’t necessarily die. One must suffer a catastrophic injury resulting in either a huge loss of blood or major damage to the head or heart to die. Even then, death is not assured. There is always a chance that someone (or something) killed will resurrect as an undead. This is usually referred to as an “unclean death”.
Thankfully, once an undead is successfully killed, they are usually down for the count. Also, sometimes those who are killed die without complications. This is called either a “clean death” or “death to completion”.
New life is still able to be brought into the world. Death is the only thing that is absent.
Many people from many races and creeds have been born into, and have only known, a world where life is never ending.
The absence of death has caused many societal and economic shifts. Some regions have dealt with the change better than others – but all must accommodate for the fact that newborns are adding to the burden of resources.