@Bad_Player
What you want to do can be easily accomplished using the world builder;
Place your demons (using an existing unit type on the map)
Rename the demons to whatever you want
Give Verdian the mission
If one of Verdian's units kills a demon, he'll tell us and you give the promo to the killing unit
If a demon is slain and it is not by Verdian, just give the promo to one of the non- Kuriotate units nearby (for the purposes if the game, it doesn't matter if it was another unit that actually killed the demon)
As regards secret plans, it's important to remember the distinction between the Gods as characters and us as players. Everything discussed on this Hermetic Lore thread is OOC.
Esus is the God of Deception, so none of the other God characters should be aware of his schemes unless I describe him discussing (part of) the plan with other Gods on the story thread or it's specifically agreed on this thread that certain other Gods are aware of the plot.
Maybe it's because Esus is so secretive about his plots that I've tried to be very open about discussing ideas. There are a number of reasons for giving the other God Players a heads up on what you are planning:
1 It gives others a chance to give feedback, if what you're proposing is excessive
2 it gives others a chance to make suggestions to help improve on your original idea
3 it allows players to help with how to mechanically implement your idea
4 it avoids conflicts, e.g. Sirona won't have an angel on Bradeline's Well
5 it allows others to see if they can plan to incorporate elements from your story into their own. Knowing that Lugus and Sirona will have prophets in the story saying it's possible to escape from hell means it's one less thing for me to do early in the game.
6 hopefully seeing other people's ideas will stimulate further ideas
7 it also gives an indication of the level of interventions that are planned, providing a benchmark if there is an idea you want to surprise everyone with by first introducing it on the story thread
There are a couple of risks with a completely secret plan, i.e. One that isn't mentioned in this thread first.
If it's seen as excessive or conflicts with another God player's plans there's the chance of different players getting frustrated with the game and either quitting or responding excessively themselves. Empedocles, as Dagda might feel it necessary to intervene to reintroduce balance.
One way to think of a DI game is as a role-playing game in which the distribution of people involved is reversed. Instead of a single gamesmaster, there is a community of gamesmasters (the God players) providing characters and plotlines for the singular player (the mortal player, Verdian) to interact with. Like a role-playing game, there's no winning or losing, there's only keeping it interesting so people want to stay involved and contribute to the story.