I never did.. so I ask for correction: 1) You need a smith character who joined a faction 2) Your faction needs to own a town 3) Your smith character needs xxxx silver in his bag (no idea how much it was, 1000 maybe?) 4) Your smith character needs to go to the smithy of the town your faction owns 5) Craft the weapon 6) You should get a context menu if you want to faction bless it 7) Voila PS: for 5) you also can use a runic hammer Faction blessing lasts 3 weeks (was like that on OSI I think) PPS: Only someone of the same faction than the blessing can wear the weapon
