Tactics against Necromancers.

Guys, sorry, I messed up – it seems the deadly gaze of the Mighty Gorgons doesn't affect the Black Knights.

Accelerated champions can deal damage, but if they get close to the Necromancer's main forces, the skeletons will give them a warm welcome, and the champions might have to say goodbye. An explosion definitely works, both against skeletons and vampires – they don't have that much health...

I agree with you that close combat with the Necromancer risks turning into a bloody battle; I got a little carried away, so it wouldn't be bad to have a backup plan in the form of a few dozen Black Knights, or, at worst, Titans.
And regarding the champions having to say goodbye after talking to the skeletons, that's not a certainty!
In my opinion, the only practical tactic against the Necromancer has always been and remains to prevent the UNHOLY ONE from developing, specifically by capturing as many dead bodies as possible in the form of skeletons!

And regarding the Mighty Gorgons, their gaze affects everyone, even the Black Knights, let alone the Black Knights.