Defensive gameplay and other tactics.

By the way, I recently played on a duel server, and I was playing as Humans, although that's not important. The main thing is that my opponent, playing as Fortress, sent his upgraded Lightning Elementals (I don't remember their exact name) to my rear and cast the Berserker Rune on them, which allows them to attack each nearby enemy without taking damage. As a result, he killed a lot of my units and won. That's how cool the Berserker Rune can be used!