Originally Posted by Blightedmarsh
Now that is nice, I will have to remember that one.
Remember however that killing is only evil if death is seen as undesirable. As astonishing as it may be throughout much of western history people lived their lives in perpetration for the hereafter. If undeath was viewed as an essential part of that perpetration or as the afterlife itself then undeath and the killing it causes would not be perceived as inherently evil.
RAW, which is what I'm trying to jive with, says that killing, in and of itself, is morally neutral. The motivation for the kill is what determines good or evil. Good is not only okay with, but condones killing if doing so will prevent future acts of evil with a reasonable degree of certainty. It's also okay with killing in self-defence or the harvesting of non-sapient livestock.
It's very definitely not okay with killing for fun, profit, or convenience. This has nothing to do with morality. Morality is a subjective social construct that is related to, but not the same as, the cosmic forces of alignment.
For some people this would not present much of a problem. For people with all important long term goals it could be viewed as a necessary sacrifice. For people who either don't care or positively enjoy the suffering the inflict on others this would be no problem at all.
In the former case you're talking about willing conversion into undeath, the necropolitan template stands out, which would be, depending on the form, morally neutral if all of the various methods weren't explicitly called out as evil. In the latter you're talking about evil characters anyway. Converting to undeath allows them to further their evil in the world. It's the exact opposite of the good done by killing them.
It's very important to remember that morality is always subjective even when alignment isn't, while alignment is objective unless your DM says otherwise.