Do warlocks not have the forge?
I think we're misunderstanding each other -- i'm saying that I think if you select "Forge ironbone mace" it will queue the job up at your regular old forge workshop. Which i think you're telling me you have access to, although you'd like to have more anvils so you can have more of them. So, I'm not saying it can't be done, I'm saying it can be done at the forge.
the very first two actions are at a building called the Corrupted Forge (SKULLFORGE)
Searching for: forge ironbone (bones & ash)
reaction_warlock.txt(1484): [NAME:Forge Ironbone (bones & ash)]
Found 1 occurrence(s) in 1 file(s)
[REACTION:IRONBONE_WARLOCK]
[NAME:Forge Ironbone (bones & ash)]
[BUILDING:SKULLFORGE:CUSTOM_I] [BUILDING:MAGMA_SKULLFORGE:CUSTOM_I]
[REAGENT:h:150:BAR:NONE:ASH:NONE][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:A:1:NONE:NONE:NONE:NONE][USE_BODY_COMPONENT][ANY_BONE_MATERIAL]
[PRODUCT:100:1:BAR:NONE:INORGANIC:RHENAYAS_DARKLIGHT_IRON][PRODUCT_DIMENSION:150]
[SKILL:SMELT] [FUEL]
[REACTION:BLOODSTEEL_WARLOCK]
[NAME:Forge Bloodsteel (ironbone & blood)]
[BUILDING:SKULLFORGE:CUSTOM_B][BUILDING:MAGMA_SKULLFORGE:CUSTOM_B]
[REAGENT:blood:150:NONE:NONE:NONE:NONE]
[REACTION_CLASS:BLOOD]
[DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:blood barrel:1:NONE:NONE:NONE:NONE]
[FOOD_STORAGE_CONTAINER]
[PRESERVE_REAGENT]
[DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[CONTAINS:blood]
[REAGENT:a:150:BAR:NONE:INORGANIC:RHENAYAS_DARKLIGHT_IRON][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[PRODUCT:100:1:BAR:NONE:INORGANIC:STEEL_DROW][PRODUCT_DIMENSION:150]
[SKILL:SMELT] [FUEL]
Searching for: skullforge
building_warlock.txt(4149): [BUILDING_FURNACE:SKULLFORGE]
building_warlock.txt(4190): [BUILDING_FURNACE:MAGMA_SKULLFORGE]
[BUILDING_FURNACE:SKULLFORGE]
[NAME:Corrupted Forge]
No guarantees, i just spent like 2 seconds lookfinding this in files and have literally never played warlock mode, so, good luck ^^