Oh, excellent! That's done it.

Now it's not actually multiplying the Essense. I'm a tad new to this, and I'm not having much fun wrestling with the small amount of resources I can find. Is there actually a <Multiplier> tag or have I misused AdjustUnitStat when it should be something else?

I think I'm starting to see how this works.

Sorry about being vague, I've been scouring the forums for tutorials and come up with stuff that I think might be outdated. Been poking through the code for the hotfix mod and trying to learn from it, but not done too well so far, apparently.

Thanks for being so patient with me, just having a hard time getting to grips with all this.

EDIT: To clarify what I'm trying to do, I'm just trying to double essense at the moment. Later, I'm going to try and make the Shard Shrines produce a small amount of spell research and a bigger boost to essense.

I'm not sure which would be more Master of Magic-like. Probably that it should just be the units with the abilities. I'm not sure which, really. I've got it working for all units, I think, so I'll provide the code.

But I think I'd like to do it only for units with the ability. How would I do that?

Now, all I've got to do is make it so that it provides 20% extra essence for each shard of your mastery type that you control. But I'm not sure where I'd do that, or if it's possible. How would that be done? I have the feeling I'll need to use <Calculate> quite a bit.

Try this. Use the multiplier tag instead of value. This tag is great for doing multiplicative stat adjustments, and is actually better than value for these types of adjustments.