The Unforged is the new name for the old Slayer hero model. It is part of the Dispossessed faction in Age of Sigmar. The Dispossessed are more accurately duardin who seeked refuge in Azyr right before Sigmar shut off the mortal realms as Chaos took hold of them. The Duardin within built up their strength and helped prepare the factions of Order for the coming war. Within the Dispossessed is what is known as the Unforged. We know little about the Unforged, but we do know they were changed by their encounter with Choas, and not in a mutation/conversion way, but in a crazed vengeful way. They are still deadly and suicidal, but instead of trying to atone for their sins, they now seek to end their life bringing Chaos down with them.
I was perusing Ebay (this is something I need to stop doing, seriously) and found the Silver Tower Fyreslayer Doomseeker hero model going for about $5 ($8 with shipping) and could not resist. I wanted to make an Unforged for my Duardin army, but instead of paying $21 for the real one, I was able to make this:
Talos project. I had to cut off his feet, repose them, and greenstuff some better ankles so it appeared like he was naturally standing on it. Otherwise it would have looked like he was on an invisible plank. Also I cut off any little icons and doodads that looked too fyreslayer-ish. And his weapon heads were replaced by Longbeard great axe heads. I think I successfully converted him to look more like a traditional dwarf slayer-type. The fyreslayer models have metallic runes embedded into their flesh. While it's a cool idea for fyreslayers, that's not the way of the traditional duardin. So when I paint him up I am going to do all those fleshrunes in regular flesh colors so they look more like tissue scarring.