Though in this game, being a Pker, or Player Killer, on its own was really a universally negative title to have. This was surely a player driven game, but to allow them to kill each other was a choice still. However, the choice came with consequences that follow them, regardless of the reasoning for doing so. It was a choice that they were given to make on their own, but they were not given the option to use it to cheat the game to finish it. How would not having so heavy and permanent consequences for killing another player result in them attempting to cheat the game? Well, that came in the same way as why they, the players, were made basically immortal in the game world of The Decagon and physically invulnerable in the reality segment of it. The developers made it so that they can not somehow manage to all kill themselves in either layer of the game to accomplish the goal of killing all the players, if they do not want to take on the task of killing nine end game superbosses from square one.
After all, another method of trying to cheat the game would be not to have everyone just attempt to take themselves out, but work together oppositely than they were supposed to. As they were supposed to work together in any manner to take out the nine demons, not each other. They were not being allowed to even attempt to plan out some kind of way that would allow one of them to accomplish this feat at all, as that would be uncertain and unfair, as the players turned demons had to follow all the rules normal players do, but they had their own unique set of rules that were in place just for them. The current focus of things is on the players at the moment, as this was in place to ensure the purpose of the game remain intact, as they were given an objective, and while they were allowed to choose not to pursuing it or engage with it, they were not going to be allowed to overturn or undermine, as those were not the choices they were given by the developers. Though if everything was player choice, then they should be allowed this, those two. That was not the case, as that was just not something that was possible, as they were all given a task, and allowing one group to choose for everyone else was not going to be allowed. Breaking the system was not allowed, as that takes the choice out of other players' hands in numerous ways, to both the players and the nine players that are now the demons.
Anyway, the strict and iron clad rule on killing was in place long before the truth about The Decagon was revealed to everyone equally. Those who killed another player within the game world, regardless of the reason, were immediately struck with the ban immediately. While matches between players were allowed, they were considered akin to true matches between people themselves. In reality, most causal matches between people are not to the death, after all. Though this is a game that allows players to attack each other, that does not mean it allows them to kill one another without the result happening. Thus, those players who kept fighting until one of them died were labeled a Player Killer. Those who even did it by accident were also labeled a Player Killer as well, even if it was purely an accident. The system that governed this did not allow exceptions.
What did allow instead was three way split between what killing another player, regardless of which layer they did it in, meant overall.
Those ways were: Player Killer, Bandit, and Bandit Killer.
Player Killer
They were just a normal player who had killed another player; for whatever reason, they were permanently banned from all settlements. While their room remained in the same place as always, they could not access the facility anymore when they logged out, as it would lead to a random place within the outside the facility. A tent was placed there, and they had to fend for themselves from there at that point. No one from the facility could access their room either from their end. The door was visible, but locked, barring entry fully and completely.
How were they able to keep this from other players? It was because they logged out the moment they killed a player, and when they logged back in, they were in a random spot within the game world. The player who was killed by them was able to log back in, but could not find out what happened to their killer, as they were no longer able to find them. Interacting both inside the game and outside of it required the players to be in front of each other. There was no friend list, chat feature, or PM system in the game, as there was a reason for this to be explained later. Player Killer would remain as such as long as they only had one kill under their belt, and killing them would result in that player becoming one themselves. The next step is what happens when Player Killer has more than one kill under their belt.
Bandit
They are players who have killed more than one player. The reasoning does not matter, as they were given a chance to just exist as mere Player Killers going forward. To go out and kill another player was a choice at that point, as it would not be considered an accident. To have more than one kill means that you meant to do it the second time around, as there were choices one had to make before they reach this point, as that's how the system was built, after all. The Bandits are mostly the most malicious players of all, for the most part. They are the players who choose to kill and do so often. Their targets are both Players and Player Killers. There is something the Bandits learned first: there are no NPCs within this world; thus, EXP for leveling had to be done mostly through Guild quests, and the EXP was decided by the Guild itself. However, there was another source of EXP that gave a boost to both level and skill, which was used for that purpose. That source was other players themselves, as a player could kill another player and gain whatever EXP and skill level they themselves had acquired.
It was one way of progress in this world, but it came with a catch. Being labeled a Bandit meant they could be hunted down themselves, and anyone who kills a Bandit does suffer the penalties that normally come with it. Also, any act that would have normally killed a player when they are within the reality segment of the game results in them instantly becoming a Bandit, as they skip the Player Killer phase and immediately become a Bandit. Cause, at that point, you either have intent or lack something.