How to kill Black Dragons?

A good tactical move would be to position yourself in a corner of the map. Due to their high hit points, the enemy units will be forced to attack you one at a time. The squad should have a minimum number of units. Before the battle, it is advisable to remove weak units and ranged units with a penalty in close combat. This tactic works well for Barbarians with Champions, Paladins with Angels, Archers with Phoenixes, and so on.