Poll: Preferences when choosing skills in Heroes of Might and Magic IV.

Only a hero with well-developed "leadership" skills can slightly mitigate racial animosity. For armies without such a hero, it's better to stick to a single faction. By the way: units with the "undead" spell, when part of an army like Sylvan, will lower morale not only due to racial differences but also by inflicting -2 morale due to the fear of undead on living creatures. In short, an angel with a devil is not so bad, but an angel together with a bone dragon is the worst-case scenario (leadership is powerless here:smile15:).