I wouldn't use it at all. It's not my right to decide. Besides, I know I would regret killing a person and couldn't live with myself for doing that.
The whole moral of Death Note was about issues like who gets to decide life and death; and how using a death note only creates sadness and misery; and that even people who think they are using the note for altruistic purposes become just as bad as the criminals they kill.
What have Satanists done to you? I'm a Satanist.
Saying Satanists should be killed is comparable to saying practitioners of other religions and beliefs should be killed.
Well okay, I don't go by the label of Satan. But if I had to pick a side, I wouldn't be with the guy who punished his kids for eternity because they were stupid and ate an apple.
Being raised Christian, I always struggle with that. If God gave humans free will, is omniscient and omnipotent, then
god knew that humans would eat the apple. Therefore, god created humanity knowing they would fail and sin and then be cast out to suffer sickness, old age and death. But why? As a test, suffering= redemption; without sin humanity will never know god's forgiveness?
Then I wonder what kind of god would deny their creations the chance to learn by forbidding fruit from the tree of knowledge? Was god scared of humans gaining knowledge and turning away from worship? Anyway, I'm going off at a tangent.
I'd do the same. Either destroy it or return it to the shinigami who dropped it. That kind of power is too dangerous for humans.