As many people as there are, so many walkthrough strategies :) . But I somehow didn't think about the rusted ones from the summoning portal in the dungeon. Probably because I play as the dungeon very rarely.
By the way, I killed CD with 10 titans with support, 1+1 Archs and 1+1+1+1 gargoyles

Good grief, how does that work - I don't quite get it right away. Write in a bit more detail the tactics of this battle and how many CD were there? I think there should have been roughly around 600 CD, slightly fewer. That was my case and I smashed them with 33 RD - without losses, but barely, spent a ton of mana.

In theory, 6 squads of CD would immediately wipe out 1+1 Archs and gargoyles with support within 2 rounds. Where is the catch here - spill it!? :)