So, been playing it for some hours now and in Act two, where the main weapon might drop from certain places according to the guide: Trozan’s Ice Shard - A cold Warlock Beginner Guide. Which is the Spectral Bludgeon.
Now, there is different items the Lord of Lost Souls drops, the shield having the highest percentage. Which of course what he dropped the first time I killed him. So, lets try again and see what it drops, which was… nothing at all of the items under Notable Loot. Neither the third or forth time he dropped any of them.
I was level 25 (not sure about the Lord of the Lost Souls though, never thought of checking his level) but putting him as level 25 as well. I know it is all random but if looking at the Lord of the Lost Souls monster information in Grimtools Database, the Bulwark is 50%, Longsword, Bludgeon and Battle Axe each 10% and War Shield at 8%. Is it right to assume that that would be a 88% of him to drop one of those items and 12% chance to drop nothing ? (Well, part from other random items but which are not under Notable Loot?)
Just curious since it seemed for me, it was more the other way around ! 
And also wondering if I should give it a few more tries or just leave it and continue my adventures towards Homestaed instead. 