Picking up this from the Layers of the Abyss thread...
Indeeed, we talked a bit about the 100th Level PC concept in this thread about adapting the Bloodstone Modules to Mystara
I really like this idea of playing demi-god like heroes in an epic module, but from what I understood they didn't really take it seriously enough. I wonder if the BECMI Immortal Rules or 3E's Epic Level Handbook would have been more appropriate for the style H4 aimed at.
Looking at H4, it is certainly not
aimed at Immortal level characters, I would say it is aimed at Master level characters - it's actually very similar in feel to M1 to M4 - characters responding to a threat to their kingdom (i.e. the one they rule) and, as per the Masters rules suggestions, going to the outer planes to do something about it.
The problem with working out the levels for 3rd Ed is that imo characters level too fast, especially at low levels, I think though H4 should sit sub 20th (rather like the end of the Savage Tides AP) but low epic might work.
Now while I agree that H4 did suggest the demi-gods play, I would disagree that it aimed at a style of it; the adventure is written for the conventional high level party and the extra levels are just tacked on (in fact I wonder if that is what happened - someoen said "we're never going to release a higher level moduel than this, let's extend it upwards"). In fact, since for dual classing you need your second class's levels to exceed your first class's to get full benefit, playing a level 100/100 character is going to be very, very frustrating - and the party has 2 of them!
So, for doing this properly, which system? I think that Epic D&D (3.0/3.5) should
be the better system, but it is so poorly written that using low level immortals rules BECMI characters will be the better option.
"If it looks like a duck and quacks like a duck, it might just be a crow".