Use the spies to take down crucial targets such as archers or shamans. But make sure they turn invisible and they are not close to any other enemies that could take them out. Use Assassins to guard your weaker units and the rear of your formation incase of enemy assassins. All melees are to go to the front lines but keep everyone within reach of healing abilities.
On the last stage, not all units need to be upgraded when they are able to do so. Like the blue mages, they can still be of use with their lightning strikes and their ice magic to damage and stun foes.
This may not be true but from what I've read from other games, the reason why we can't register our families is probably because of the flash updates. It's just a thought. This game is pretty old.
I really love the cosmetic system. By using weapons you collect as skins, you could make your character the style you want without worrying about stats.
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