Please post here if you are interested in a Demi spell. It would cut the targets stats in half, and even scale it to half size.

The problem with such a spell is that any scripted effect which works off of "modav health" ends up being a perminant change. Meaning that if you, or a companion were hit by it (in the case of reflect spell), you would always have less than your maximum health, and would not be able to recover the difference. As there is no other way to achieve a 50% health loss, use of such an effect would be illadvised. And unlike in the FF world, something like this would be rather easy to exploit as an enemy can be hit by a spell several times before they come into melee range.

I was under the impression that using modav2 only made temporary changes.

Don't use OBSE, so cannot comment on that one. May still have similar issues in regards to health changes. And regardless, it still has the same potential of being overpowered.

Hmm... You'd have to create 2 different spells, 1 being the scripted animation shot, and the other, Drain/Damage Attributes. Maybe you can link the Drain/Damage spells to the Script?

I use OBSE a lot for scripted spells as it gives you more access to the "internal" game functions. As for overuse, the script can check for things such as factions, level, and resistances. It could also be a power to limit use.

I'm well aware of what OBSE does. Just not aware of the various limitations and quirks to all of its functions. By many accounts, even one usage could be seen as overpowering. A boss with 2000 health for instance, would be taken down to 1000 health from a single spell. As that would likely trigger them to use healing spells to recover, they would be open to anything else which might do more damage than their healing spell. Regardless of how it is "limited" a spell which removes half the health of anything it hits would be overpowered since Oblivion combat is centered around few, long fights, and not many, short fights (like in the FF series and similar). As is, it's nearly impossible to design a dungeon which is difficult for over-powered characters, but still possible for normal characters.

Fair enough. What about selected stats other than health and magicka? The spell could have a duration, say 10 seconds and then revert. More like a drain, but scaled for half of the stat.

Quite hard to make a formula for every enemies' stats to be referenced... Maybe it can only be cast on one enemy, and until the effect wears off, it cannot be used on any other enemy.

When the script occurs, the enemy takes drained attributes, set accordingly to half (and rounded by 1) to their stats.

But then this might mean for 1 enemy, 8 stats needs to be referenced and calculated, and 8 drain attributes will have to be used.

Actually it's fairly easy to do since the script will run separately on each target. And it doesn't have to affect everything, maybe just the core 8 stats. Each "drain" is done by: set drain to ((target.getbaseav stat / 2) - target.getav stat).

Example: if the target's base stat is 50, and the current stat is 40 (due to magic damage/drain) the half-way point is 25, and the drain is -15: 40 - 15 = 25. Using a doonce and allowing the if condition to run on update means no enemies get missed (maybe 1-3 frames for all enemies to be drained, depending on radius and enemy concentration). Very low FPS hit if this is just done on one enemy.