Illusion of victory.

Take, for example, one nuance: I have demon troops allied with knight troops (allies are supposed to strengthen the armies of allies, but they might not): how am I supposed to know that?

The fact that demons are allied with renegade troops is clear from the videos.
The fact that demons use illusion magic to hide from humans is clear from the videos and the description of the quests.
The fact that allied units join a friendly faction is an obvious conclusion that follows from all of this.
Deciding whether to accept them, kill them, or leave them to the allies is your personal in-game decision and does not require any prior explanation.

In my opinion, it doesn't make sense to over-explain very simple things if there is no desire to spend a small amount of time carefully reading.