>Heh, it's painfully obvious once you start dealing with
>fiendish ice devils that they're about six steps above even
>lesser ice devils. Those things are just wrong.

They only have an extra spell or two, IIRC. Without doing the math I don't think they're likely to be more than a level or two higher.

>I seemed to remember a comment that players won't see all of a
>familiar's abilities at level 17, implying maybe that you got
>some stuff at higher levels with familiars.

Again, assuming I remember what I was talking about, the main implication of that was that you might have a familiar with abilities that wouldn't be relevant until a higher level, not that you wouldn't see abilities on skill until later. For example, you get familiar at 17 and some familiars have abilities that modify conjuration spells (all of which have echoes when relevant) so if you have a familiar that helps you with elemental summoning, that isn't immediately apparent at 17 since conjure elemental is 3 levels later.

>My question was more, are there devil abilities that you (or
>the summoned devil) have to be a certain level to see? Like
>where bloodthirst does X, Y, & Z at hero, but only Z at level
>35.

Abilities on angels/archons/devils/demons are set by servitor "class", e.g. abishai/bearded/barbed/ice, not by their actual level. That being said, they cast their spells pretty much at their level just like a shaman or whatever would, so wrath from a level 40 angel is going to do more damage and last longer than a level 30 angel's, just as a level 40 paladin's wrath does more damage and lasts longer than a level 30 paladin's.

Servitor level is somewhat correlated with class, in that the large mana pump and a bit of luck that it takes to get a lesser archangel instead of a winged angel also "buys" extra levels for the angel, but theoretically there's no reason a level 35 conjurer can't have a devil which will Rot you -- it's just unlikely to have much in the way of killing power because of its relatively short duration and the tendency of people in a level 35 conjurer's range to not have a 6 CON.

>Or are fiendish ice devils as absolutely terrifying at 40 as
>they are at hero?

In terms of the spells they can cast, they are, but the hero's devil is likely to be a lot higher level.

For a number reasons which tend to compound on themselves, a lower level conjurer is much more likely to have a lower class servitor than a higher level conjurer. The Veil is a factor here, as well.