Level 20 - Succubi!

I found the warlock's voidwalker minion is a passable tank while I used it. However, now things are different. At level 20 a warlock has access to a quest for the next minion. That minion is a succubus, with high damage output but less of a damage soak than the voidwalker and without an area threat move. That however suits me just fine.

From using an imp and two voidwalkers I swappted to using an imp for his stamina buff and two succubi. Besides clearly better looks this demon's damage output is really noticeable. It is extremely rare that one of my succubi dies. With two of them going at a target and my team blasting the target to smithereens at the same time there is simply no time for the mobs to deal enough damage.