Spill, let's follow our old tradition and take the zombie stronghold on level 111 for all castles ;) I'm just too lazy to come up with something myself -_-
I can show anyone, maybe someone will record it later;)
And the bonus can be different (spells, heroes), you can also take it for other castles, I think.
P.S. I wrote an army for the Necropolis using the Cove (approximately the minimum), you need more for the zombie stronghold so that the losses are acceptable.