RULE2

2. NPK (Neutral): (Refer to LPK rules, as some LPK rules roll-over to NPK
   Rules that do so will be clearly marked as holding true in NPK
2a.
  Please do not attack a player who is fighting mobiles. Even though there
  may be bugs to exploit, do not use them to attack a player while he is
  engaged in a battle with mobiles. If a player is in combat with another
  player before a mob attacks, it is not considered illegal to kill that
  player. This rule means if a player is in combat with a mob FIRST, THEN it
  is illegal to fight the player or in any way help the mob. This includes
  fearing, sancing, or healing the mob.
  Also read Help "MOB INTERFERENCE" and follow the rules there.
2b.
  Do not attack your form in NPK This includes joining a formation,
  unforming and attacking while in the NPK area (the same holds true for CPK
  NOTE If you enter a zone in formation, you can't PK each other until
  10 minutes has passed since you unformed, or until you have both left
  the zone. This applies to both CPK and NPK It doesn't matter if you
  were formed in lawful, unformed, then went into NPK or CPK You still
  can't PK each other until after 10 minutes or after you've both
  completely left the zone.
2c.
  It is illegal to resurrect someone then PK them in a GRAVE NPK zone. In a
  normal NPK zone, this is NOT illegal.