Okay, so I have this big boss fight where the player goes up against 3 gigantic atronachs (the giant flame atronach looks SCARY btw) and so far everything has been going swimmingly. I've edited their stats, made them all really hard (the Frost has as much HP as Alduin), and in general the boss fight is going pretty well.

The one problem is that the Flame and Storm atronachs use spells, and the spells that they use are not suitable for high level combat. It doesn't really matter how big and scary a flame atronach is when its throwing Flame atronach fireballs at you for 10 mana.

Basically all I want to do is change the spell that the Flame and Storm atronach's use by default to something with a little more oomph. Can someone help me, or guide me to a tutorial on customizing enemy combat behavior?

Hmm I got my Flame atronach to cast fireball. I may be able to do this myself.

Please post how you do this if you figure it out.

Actually, it was relatively simple. All you have to do (at least in the case of Atronach's) is delete the crFlameAtronach spell that they natively have, and then put in what you want. I put in Fireball, and it works like a champ. I also gave my storm atronach Thunderbolt, and he seems to love it.

There are some things I'm still not clear about though. For example, I wanted my gigantic Frost Atronach to behave like a giant, but when I try to give him Giant spells, he runs away like a pansy and doesn't fight. I think this may have something to do with the fact that under attack data his race is FrostAtronachRace, and if you look at FrostAtronachRace there is no ability for him to cast spells. I am currently looking into replacing his Combat Data race with Giant and seeing what happens. I'll let you know the results.

Preliminary results of my Giant experiment.

Inconclusive: I have changed his race data under Override from Behavior Graph to Giant and given him all the giant spells. Oddly, he seems to enjoy using the Giant Magic Resistance spell, but he won't use Giant Stomp or Giant Club Slam. I suspect it is because he does not have the required animation. I'm going to see if I can give him the animations to make him into a giant, but I'm not terribly optimistic.

Also, I tried making a giant into an Atronach by the opposite process. I made a Giant clone, and then replaced its race with Frost Atronach. It works in the sense that the giant atronach will render, but failed in that it also will not attack. I think you can replace spells and combat information ad hoc, so long as the new combat data has all the requisite animations within the race that you're using.