1-Hunters: They deal a lot of damage, plus invisibility will be very useful if you need to sneak up on an archer or a valuable enemy unit.
2-Megeras: They deal more damage and run a little further. If you increase their speed with an artifact and tactics, they become a real monster, and the enemy won't be able to retaliate, avoiding losses.
3-Minotaur Gladiators: Constant morale (+1) allows this unit to move frequently, plus hitting twice per battle is a bit of a cheat, but it works.
4-Dark Riders: More defense and damage, they're like raiders... a bit underwhelming.
5-Venomous Hydras: They regenerate twice as much as cave hydras, and have more damage and defense, plus they have 2 counter-attacks, one with blood and the other with heads.
6-Priestesses: A ranged unit in the army is always useful, and dark spells will also be helpful.
7-Black Dragon: No need to say much here - damage, defense, and magic resistance are all good.
Well... that's all.
2. The difference is only in stats, and resistance to debuffs, which is situational.
3. Surprisingly, this is also situational. Both upgrades are viable.
4. Yes, Dark Riders are much better than the alternative. The alternative is completely useless. At least you got this one right.
5. Venomous hydras don't regenerate, they have less health and are taken down faster. In very large armies, venomous hydras are better, but the dungeon is already on its last legs, and the hydras won't save it.
6. Useless ranged unit or useless invisibility? It doesn't matter. They cast the same spells, so there's not much difference in which tier 1 unit to take.
7. Red units have a good ability, don't underestimate them. Although black units are needed more often.
