Kill stealing is NOT against the rules. (If you don't even know what it is, go ask somebody or just decide not to care.) Now, it IS considered "rude" by many people... but you will never be punished for kill stealing.
What you WILL be punished for is harrassment of somebody else who you are yelling at because THEY "stole a kill." So if you are running about and decide to be rude and steal peoples kills or whatnot, and those people start to harrass you, please report them via the CONTACT US button so I can destroy them.
Thanks for keeping the Dark Grimoire a constant slaughterhouse of demon corpses and a safe place to go without people yapping and whining at you.