Overclockers Club published a review on the Scourge Warlock Mod 13 Build Guide
A quote from the article:
Some other good artifact choices are the Wheel of Elements, Sigil of the Devoted, and Thayan Book of the Dead. The Demon Lords’ set is really expensive and difficult to acquire, so I recommend the Black Ice Beholder set as an alternative; it has Constitution and Charisma, and stats that you need. As for companions, I focused on increasing my damage.Scourge Warlock Mod 13 Build Guide @ OCC