Item description points you in the right direction
Do another Demon Tower run up till the black smith
If you have Soul Vessel in your inventory and are atleast Level 90 you have a new dialogue option
Goal is to defeat the Blue death and the rewards he can drop are event coins, event potions and some other stuff, * Can be repeated infinetly but you always have to get the soul vessel from the death reaper which is not tradeable etc.
After the blue death another blacksmith spawns that grants an additional +10% Refinementchance and takes no items to upgrade
