forge level 50 shadowkill armor (purple) then go to soul hunt and exchange your blue/red stars for spirit shadowkill stone and press the "reinforce" button and "spirit forging". click the piece you want to spirit forge and voilaaaaa there you have it
Lvl 50 spirit forge isnt that good...use it as your last resort......... Its recommended that u dont waste stars for spirit forging lvl equips and wait till lvl 70 and beside it takes just a week to get to lvl 70 from lvl 50
And for spirit forging any equips get the spirit forging stones by exchanging the stars of soul hunt in the exchange area of soul hunt window...for lvl 50 its called the spirit shadowkill stone..then go to reinforce and spirit forge.....btw it takes 15 stones for the weapon and 9 stones for the other equips