Before I go on, I should explain what might happen after death in the realm of my birth.
After someone died, their spirit would go to one of several possible afterlives. Most would go to the afterlife most-aligned to their race - elves would go to a great elder tree, animal-people would go to an eternal hunt, and so on. Others might go to an afterlife based on their works in life - warriors would find themselves in an endless cycle of feasting and battle, farmers would forever tend a perfectly cooperative farm with ever-fair weather. There were many graveyards but they all had one thing in common - nothing there ever changed. Most saw such things as fulfilling and welcome rewards after a life of toil, but I was never comfortable with what awaited me. In fact, thinking back on it now, maybe that same sort of dissatisfaction was a reason that people sought out undeath and other ways of subverting death. In any case, I didn't want my toil and trouble in life to be without meaning, and once I started adventuring this feeling grew far, far stronger. Thankfully, there was another way.
There was a type of magic that changed your spirit. Instead of proceeding to an afterlife, you would become some other thing. Depending on the ritual you underwent, after death you might become a unicorn, a being of ice, a vampire... any number of things were possible. You would lose part of yourself in the process, though - you would no longer be the adventurer you had been, and were now a, I don't know... a magical narwhal who had the memories and much of the personality of who you were, but you'd be a magical narwhal doing whatever magical narwhals do. Some people sought such magic out because they truly wanted to be this thing, whether they wanted the power or to carry on the work important to them in life. Others sought these magics out since they did confer some benefits in life. Some, both.
As an adventurer I hated the thought that when I died, all the work I did, all the good I tried to do, all the battles I endured would be utterly beyond me. I would rage in the afterlife, unable to safeguard the work I did or see to the causes I fought, cried, and bled for. A normal afterlife would be utterly meaningless and I would be too. Finding an eternal impotence abhorrent, I sought out those transformational magics. I was interested in two specifically, one with great personal significance or one that would bind me to the greatest endeavor possible. The former would turn me into a being that eternally sought out and destroyed undeath. I wanted to destroy liches, vampires, and such not only on their own "merits" but even more so because necromantic magic harmed the world itself. A worthy thing to be certain, but it wasn't the magic I obtained.
I eventually become a master of time and existence itself, and even though I died with no transformational magics upon me, it was critical to the great work of my life - destroying, purifying, and resurrecting a corrupted god.
~A