Social Slayer was introduced on the 11th of July of 2012

Social Slayer was introduced on the 11th of July of 2012, and allows two (2) players to participate together on a Slayer assignment by inviting each other using an enchanted gem or a Ring of Slaying. To invite someone, both players must not currently have a slayer task assigned, or both players are on the same task.(NOTE: Due to technical reasons, if you have had a task before 11 July 2012, you must finish that task before you can invite other players with the same task.) Drops are not shared unless using Lootshare or Coinshare in a multiway combat area. Combat and slayer experience are not shared with each other. The aim of the social slayer is simply to speed up the task and provide an opportunity to interact with other players. A single co-op point is obtained by both players when the assignment is complete. If eligible, each player will also receive normal slayer reward points, depending on how many of the kills in this task were performed by the player. For example, if both players killed exactly half the number of the appointed task, then both players would get half of what they would have normally gotten, if 1 player kills all monsters, and the other players kills none, then the first will get all slayer points and the second will get none.

When using the “Kills-left”-option on an Enchanted Gem/Ring of Slaying, the killcount of both players is taken into account, separately. Once the task is finished, the player who made the most killing blows and did the most damage will receive more slayer experience than the other. Due to this, social slayer is most useful when the Slayer group members are about the same level, as with imbalanced combat levels, one player may finish the task faster than the other. Also, in order to receive slayer experience, a player must either do the most damage or make the killing blow. Furthermore, if both players are not standing relatively close to each other, their kills will only count towards their own task and not the other player’s.

Currently, if a player deals more damage and/or makes the killing blow, the other player’s killcount will not go down. It is unknown if this is a bug.

When getting a new task, only the blocks of the player who asks for the task are taken into account. The block lists do not combine. Both players need not be present when receiving a new duo task, so long as they are in the same slayer party (easily checked by right-clicking a slayer gem or ring). Also, tasks can only be assigned by slayer masters that both slayers have unlocked and are eligible for – a team with a level 86 and a level 171 cannot receive tasks from Kuradal. (Attempting to do so does not assign a solo task to the one eligible player.).