The red-bordered Heroes are called Attack Heroes. They exist for one simple function only: to hurt your enemy in as many ways as possible. Roughly speaking, the Attack Heroes are divided into ones that cause damage and to Curses.
Curse… Heroes (like Second-Rate Troops or Worthless Equipment) lower the abilities of the units they are used on, making them easier to kill. Use them to weaken strong groups before melee or to make sure the tougher enemy units behind the cursed ones have to linger behind while their unfortunate friends are trying to fight with their lowered stats. Curse Heroes can only be targeted on enemy troops, so you can cast them directly to a melee without harming your own soldiers.
Damage Heroes (like Hellhound or Cannon) are simple: They kill, maim, slash, crush, burn – in other words, cause damage. The differences between Damage Heroes come not only in power, but in size and shape of their effective area. Damage Heroes do not distinguish between friend or foe, so use them at your own risk or suffer some “blue-on-blue” casualties
