Player versus player rule
Rules of Engagement are one of the 5 golden rules of Arelith servers. The following are few explanations and clarifications for it.
Player killing MUST have an roleplay reason supporting the conflict, and the reasoning of "Because my character is chaotic evil," is not reason enough. Being chaotic evil is not the same as being a certified psychopath, and psychopaths get themselves removed from society anyway, which, incidentally, is exactly what will happen to a character or player who chooses to act like one. Be sane and pick your battles. Challenging someone to mortal combat just because they called you a big old bed-wetting doody-head is ridiculous.
On the other hand, PvP is quite allowed. Don't be surprised if, after you've annoyed the nine hells out of someone who can wipe the floor with you, we rule your resulting death as "suicide."
Roleplay before PvP
Interactive roleplay before PvP battle is mandatory. The same applies to any non-lethal or simply aggressive action, such as Hold spells, Blindness/Deafness spell or Stunning Fist must all be roleplayed.
Tips for assassinations can be found in article about Assassin.
It is possible to attack a thief immediately after detecting Pickpocketing attempt. Just consider if such act is in character to do and if some other roleplay avenue is not possible instead. (Is the thief running? Can I alarm guards instead?)
Roleplay after PvP
Rules and tips about events after PvP are described in article Twenty four hours rule.