Heart of the Night

Well, they shouldn't have showcased that feature on streams; otherwise, it wouldn't have been patched. Besides, everything was manageable there; the only annoying encounters were with ghosts and vampires. Honestly, I don't quite understand the problems with the first Necromancer; he's a very straightforward enemy compared to others. Sometimes, he can even be defeated with almost no losses, and the losses of fairies/dancers on him, in my opinion, aren't critical and are compensated by reinforcements.
Agility was also added specifically at the beginning to make the dragon more resilient while it's still being developed.