Sworn enemy.

Why only up to 5? It would be more interesting up to 7-8! And super luck isn't needed.

Well, to get 7-8 luck, you need a horseshoe of luck, a lion's crown, sandals of the saints, and a luck bonus (you can also gather luck and morale from various altars before a battle, but it's risky, and it would be a shame if it lowered your stats). Such artifacts are hard to find. And in a quick game, it's already difficult to get 5.