In Rosh Online, conflict and war plays an integral part of the game. All players level 36 and above may kill and be killed by other players. At level 36, the PK button on your player interface becomes usable. When the PK button is on, you are able to target other players for combat; turning it off will ensure that you don't accidentally enter combat when you don't wish to (while hunting, for instance). The PK button does NOT protect you from being PKed by other players.
Player-killing in Rosh Online is guided by the Moral Value system. If you kill players, your Moral Value Score (shown on your character bar) will decline. If you engage in PK a lot, your MV score might fall to a point where you start incurring penalties: town guards will attack you on sight, your access to shops is restricted, and you may drop items when killed and earn less experience. However, killing monsters and players of low Moral Value will increase your MV score and remove these penalties.
PK and Moral Value (MV) IGN DeviLHunteR
1.All players of level 36 and above may kill or be killed by other players. At level 36 the PK button on your players interface becomes usable. When the PK button is on, you are able to target other players for combat turning it off will ensure that you accidently don’t enter combat when you don't wish to.
2.If a Player kills another players, he/she gets negative moral value.
3. Negative moral value (MV) has some disadvantages, if a player with negative MV dies from other players then he loses XP and may lose items, the loss of items depends upon the mv. If you kill a person 1 time your mv will be like -2.5k but if you keep killing your mv keeps going down until -51200. If a player has MV greater than -7000 they start losing their weapon and armor. Guards outside town also attack players with negative mv so stay safe :)
3. Killing other players increases your PK count and gives you 1 Fletta point if he/she is almost your level and has at least one Fletta point.
4. Players can regain positive mv if they start killing mobs, mobs of same level give more mv than low level mobs if player keep killing those mobs they can become positive mv and they are not outlaws anymore.
Please see the PVP for Guild Wars for more information