Just like in the first Overlord Life Force means more minions. Which is a key factor in both Overlord and Overlord 2. Now I advise when you reach a point in Overlord 2, in your Forging options when you have the right smelter there will be a helmet called The Evil Eye get this as soon as you can! When wearing it instead of only getting one life force for a kill you get two trust me it adds up. Then go to the Empire Sewers there will be houses you can knock down and when you do it opens a gate letting out big frogs. Post browns reds and greens. I just used a lot of greens. Put them on a guard maker they will attack the frogs and after they are killed two more will come out and so on it will never stop popping out Frogs until you close the gate or leave the area. They drop brown,red,green and then after you get the blue minions blue life force. Just repeat until your happy;)
The Spider Queen is one of the more significant bosses in this game.
We've put together a video of hwo you can go about defeating her. If you prefer to read how to do, then check out this page of our guide which deals with the whole Spider Queen Temple Level : Go to Overlord 2 Guide