The Player killers Hero Leader is located at Tower Of Hell 3, Coords: (X: 131; Y: 111).
There Are him subdits Around (PK Hero Warriors).
You have to talk to him if you want get the PK Hero Set.
PK hero set can only be equipped if you are in Criminal state.
There are a PK set for Warrior And Mages.
This are the cost of every part of the Sets:
Be PK have High costs, you know you have not teleports in City Hall.
There is a trick for go to Dungeon Level 4 (Demons). In Black Smith you can buy a Dungeon Level 5 (New Map) ticket for 1 millon gold.
You have a nexus between Dglv5 and Dglv4
But you can get some bonus too..
When you are PK 15+ you will get Extra Damage in Warriors, and Extra MP recovery in Mages.
Also you will revive in a PK City Revival.
But all your defences of sets (MR-DR-PA-MA) will decrease.
If you up your points to PK 20 or more, the people of your same city will drop to you.
Think good before you made a PK player, i think is not so good idea.
You can check your decrements of defence, and if the PK bonus is activated by the /checkdefence command.
But this are the official bonuses:
+2 of physical damage in PK+15 Warriors and +1 with PK Sets (this means you get the same bonus like Hero Set, but +2 for be PK+15 player and +1 more for have the PK Hero Warrior Set Equipped).
(considering a warrior: 130 str or more and 150 dex or more).
This bonus is so good for hunts and raids of a lot of people, but remember your defences will decrease.
Bonus for mages +50 of MP recovery to PK+15 Mages and + 30 if you have PK Hero Mage Set equipped (The set Also have the same damage and HP bonus of normal Hero Sets).
(considering a Mage: 130 or more Intelligence and 150 or more Magic).