One of the big problems with massively multiplayer games is the issue of player killing, with some games simply preventing you from hurting other players, while some have seperate PK servers, or make it so that only consensual player killing is possible - you can only hurt another player if they are themselves a player killer. Atriarch is taking a rather different approach, as lead designer Serafina Pechan explained in an interview on Atriarch Vault.
"Atriarch's combat system focuses on non-lethal combat - knocking a player out is sufficient to loot a body and gain experience. Killing another player in many cases will lower your experience in non-lethal combat, which is really where you will gain the most experience, so basically you will just be hurting yourself."
The game's combat system also differs from the usual "select a target and press the 'whack' key" approach of most online RPGs, with "different fighting styles you can study, and lots of different moves a player can learn". According to Serafina, "a player having more control over the combat will make it more fun in my opinion, but for those that don't want control, there is always the auto-fight key".