Slag

Slag is the current leader of the Forged, an especially fanatical gang of fire-worshipping raiders established in the Saugus Ironworks in 2287.

Background
Slag is the leader of the Forged and is originally from outside the Commonwealth. When first accepting recruits, it was a slow process, as many of the recruits died early in the trials. At some point he engaged in conflict with the Gunners and killed many notable members, which inspired more people to join including several former Gunners. By the time the Sole Survivor reaches the Ironworks, he has a strong, well equipped raider army.

He wields Abraham Finch's Shishkebab sword which Jake Finch gave to Slag to gain his favor as an offering in order to join the Forged.

Quests

 * Out of the Fire: Slag and his gang are in the middle of the initiation ritual of Jake Finch when the Sole Survivor enters Saugus Ironworks's blast furnace. Whether the Sole Survivor decides to save Jake or not, Slag will be hostile after a short dialogue.
 * Here There Be Monsters: If Slag has not been killed previously, he will be leading the initiation ritual of Jake Finch in the blast furnace and the Sole Survivor will have to kill all the Forged to recover the dampening coil.

Appearances
Slag appears only in Fallout 4.

Behind the scenes
Slag is a byproduct from the process of smelting to separate a metal from its ore.

Slag Slag Шлак Шлак