Oh j thought you just need the ember, then give it to the smith in bastille? Is there more to it then?
A little. Someone further game might be able to confirm if stones can be bought from a trader, but I've only found 1 or 2 stones to infuse a weapon so far and I'm further than Iron Keep. You need certain stones to infuse to a certain type. Look in your inventory to see if you have any stones that you've picked up.
Easy stones can be aquired from the cute petrification lizard things in the giant boarded up hole in shaded ruins, good drop rate too.
yeah its pretty cool. Though a bit of a stamina drain if u like the fancy moves. The DPS is excellent though. Put something like poison damage (either infuse or buffed) and its freakish. I vastly prefer the smaller-ish weapons to the large slow weapons. Im using it as a mundane weapon atm but will buff it with a variety of stuff (dark, poison, lightning, resonant weapon etc)
Mundane is the only way to go, if you have the dex for a Santier's then you'll have enough for a whip, which is better for applying poison to things, beware though that twinblades like the Santier's are absolutely awful for PVP, they are the easiest things to parry..