I am making a monster collection game with a friend of mine, we are 50/50 on the project, I came up with the idea and concept, I am handling the business side of things, programming and designing. My friend is a trained artist and is doing the concept art, some in game art, directing freelance artists and making promotional items.
My initial concept for the game was for all the characters to be necromancers, and so all of the monsters that can be captured and battled are undead, skeletons, ghosts, spirits and so on.
My friend tells me that this would be too boring, and that there needs to be demons too. However I want to keep a very narrow undead design- no horns, tails, extra limbs, wings, features all over the place. I want all the monsters to retain more humanity than that.
My problem is, I respect my friend as an artist and designer, and even if he is RIGHT about the game being better with a demonic element, that simply is not what I want, narratively and thematically. How do I tell him that it is non-negotiable without it sounding like I do not respect his option, his experience and his talent?
(I understand that this is something that should have been ironed out before we even agreed to make the game together, but I guess there was some miscommunication)...