Rubi-Ka is a place with a past, present and future. Player-killing should be motivated by the characters and the story, not out of boredom or the expectations of big rewards. People killing other characters from the same side will be looked down upon. If a player kills within the civilized areas around the cities, it will become difficult to enter the cities of that side in the conflict. The most important feature we possess to deal with player-killing is different zones.
Civilized areas have guards that react to player-killing.
But all zones are part of a world. There are no artificial combat locations. Some of the monsters are intelligent and not controlled by any of the sides. There are always neutrals. But without a group with a wide range of skills in a team, it will be difficult to survive some quests, and I think a fighter on his or her own will evolve at a slower pace.