Mod requests (orders).

Hello. Where should I start... Could you please advise on how to create a mod that turns a single-target spell into an area-of-effect spell, if possible? For example, vampirism affecting an area of 3x3 cells. I've been struggling with this for about a month now.

I'm afraid that such things can only be implemented if they are initially provided by the game mechanics. Otherwise, it's pointless to try. However, for the single-player game, there's an option: combat scripts. Try creating a spell whose activation triggers a script. And in the script, apply vampirism sequentially to each cell in the 3x3 area. I'm not sure if such scripts are possible, but it's worth a try! This will only work in single-player mode.