Necromancers – “The Bait” [Campaign 3, Mission 1]

There was a bug in version 1.0 with dragons, but it was fixed with patches. Darkness is good with slowing and weakening effects. Slowing + acceleration, and the color of the attack bar starts to look very appealing.

Not bad, but you have to dedicate an entire skill branch to it. In principle, it's fine without Darkness; it's quite difficult to get Darkness for Elves. You can reduce the 3 stacks of undead with Storm Wind, and then they also have sworn enemies, so they are defeated normally.