Even disregarding backlash, there is no possibility of assembling a massive Undead army.
The biggest issue is spiritual power!
No Necromancer can suppress a wild Undead army. Even in the Sanctuary, the number of Undead that can be contracted is limited.
On the other hand, if you create them yourself, it's different. Before Undead creatures develop intelligence, they can be contracted freely.
This is why Necromancers like to slaughter living beings!
Ordinary civilians certainly can't match soldiers. To ensure the combat effectiveness of the Undead army, they must devour each other.
It usually requires slaughtering ten times, or even more people, to make up for it.
If you really kill on your own and turn them all into Undead creatures, you will surely be affected by the resentment of living beings.
Many Necromancers fall not because of their evil nature, but because the slaughter is too heavy, and the gloom invades their mind.
