Krump, my dwarven fighter thief, is about 50,000 xp away from his first HLA.
When I take UAI and then cast something from a scroll what level will the spell be cast at?
anyone know?

I'm not 100% sure on this. However, since UAI is a thief ability, I imagine if the spell is level based, it will be cast as your thief level. What spell are we talking about here?

I would also imagine that any pre-existing level limits would also be in effect. For example, fireball has a maximum damage 1d6 per level up to a maximum of 10d6. So even if your thief is over level 10 (which he has to be if you have UAI) you still do a maximum of 10d6.

By the way, you are playing my most favorite character ever of all the times I've played through the series. Nothing compares to a dwarven fighter-thief. Most people don't like that race with that class, and overlook it completely because dwarves can only get a 17 in dexterity to start.

I think the max level for casting from scrolls is 10, but don't quote me on that though.

Hope this help.

Well, I got the xp, got UAI, and timed the duration of mislead.

84 seconds.

So Im casting at my fighter level, (Krump is 14/17 at the moment, so mislead would have lasted an extra 18 seconds if cast at thief level).

Which spells?
Stoneskin
fireshields
spell immunity
mislead
blur
mirror image
probably vampiric touch

And any other spells that only affect the caster, or require a melee attack to work, or that I've got multiple scrolls of and aren't worth selling.

Also, I want to know if improved haste+mislead+SI:Div+critical strike, whilst attacking from behind, will work like an extended duration Assassination/GWW combo.

I chose a dwarf because I've done halfling and elven fighter thieves before and wanted something a little different. I have to say that there's something uniquely satisfying about this guy. I think I'm going to have to find a microphone and someone with a Scottish accent to record the battle cry
"Stitch that, ya b*****d".