New units in Necropolis. Discussion and selection between upgrades.

1. It depends on personal preference, what tactics you plan to use, and which hero you have.
2. There's no need for upgrades here; they already have good attack and defense, plus a special ability.
3. Spirits and ghosts seem to be the same, but it's better to upgrade them, as they have a higher chance of missing.
4. Higher-tier units are definitely better. Are they meant to counter Vampires? This isn't in the spirit of the game, even though they are weaker, but at least they don't have retaliation!
5. Early on, after Archliches, you can divide the higher-tier units into two equal groups.
6. I'll start with Messengers, and then switch to Banshees, because if you use their special ability on a group of Banshees, it will be more effective than using the Messengers' special ability, even though they have higher stats.
7. Bone Golems are the only ones that are better in terms of stats; Astral units only have Sorrow, and even that is weak. So, they are less effective than Bone Golems.