"It is better to be violent, if there is violence in our hearts, than to put on the cloak of nonviolence to cover impotence." Gandhi..
If one does not act upon a feeling it often causes pain upon oneself, besides those who kill and are killed do only so because they are allowed to, otherwise they wouldn't be killed and or wouldn't kill, this is ordered out by a high being with power.Like how you may have been commanded to act in a certain way.
The fact one may or may not regret an action is only because they disagree with the feelings or actions that they might have had or acted out. Though regardless you and or others may have done so, and in same cases against their free will, because all movements and actions have been contemplated and are being actualized over and over so that through repetition new things can be forged from the old events. On this note their are those who's blood-lust is only ever quenched when they finally understand true knowledge when they are forced to contemplate, others will just loose theirselfs to insanity. An example of that is how some in jail often those in for life, turn their life around.
Everything happens for a reason because of the preordained events in which the first transcending being has contemplated. All knowledge reveals itself through the actions of everything and every action needs to be actualized before all knowledge is contemplated and revealed.
No action is either good or bad, though either only has a name because people may or may not understand either. But knowledge of both only means that they equal the same outcome which reveals that they are the same because of their evolution. Acting upon the nature of oneself is not evil or good it is as is, because we were born that way and the destiny and actions each individual needs to act out to for fill the great collective consciousness's knowledge, will be done regardless.
As evolved individuals we will always have free thought and impulsive actions that may act out of the order of things because of our natural reactions to anything and this is how new knowledge is created, though ones again neither is evil nor good because of its evolution and outcome.
Malanu, those who are commanded by a higher power any higher power, to act out an action do so because they were commanded to, by a higher power..
Natural selection is an appendage of the first being, whom allows death to uphold the strengths and weakness of those involved, this allows evolution to flourish.
As a result knowledge arises from the corpses of those whom uphold this arcane law. This is why people look towards the "positive" side of things so that may understand
and learn from the events in which they may have not understood.
When in your gut you no weather you should do something or not, though you still do it, this is a small example of Another being using another as theirself.
Afterwards one may regret their actions, but they never had a choice to begin with. You have done no evil.
With all this said, few will actuly understand it and even fewer will learn from it. Though those whom are meant to will.