Your HQ Background.

[QorDaq]

You make a very good point there CynthiaLee, in the real world things are rarely so simple as to be strictly good or evil. In high fantasy we tend to think of the goblin/orc/undead hoards laying waste to a village as purely evil--yet rarely frame it as such when the party stumbles across a Goblin outpost and reduces it to the last warm body before looting everything of value...*Chuckle*...

Which of course supports the idea of having a backdrop that is unique to the group playing the game.

Another advantage of going generic is that you can scavenge ideas from many sources... HQ version of Gygax's ToEE anyone?

maj!

[slev]

Actual Warhammer things in HeroQuest:
Fimir
The *design* of the gargoyle
two maps
The background to the ruined dwarven holds
The name Karak Varn
Skaven, if using the material from White Dwarf
The way wizards see magic in the fiction
Some art

Everything else is either generic, or even ripped off of somewhere else (such as Moorcock or Vance).

It's quite simple to file the serials off to be fair.

[knightkrawler]

The term Chaos Warrior should be avoided, too. Yes, generic, but there's a history of legal bullshitting by GW with the term Space Marine.

[Big Bene]

I will even find a different term for chaos, although I plan on incorporating a similar concept into my world.

The concept of chaos as used by GW is entirely looted from Michael Moorcock, down to the "Star of eight Arrows" Symbol. If the last surviving grandmaster doesn't sue GW for copyrights, he probably won't sue you.

As for the original question, it only makes sense if one wants to remake the original HQ background as close as possible, just avoiding the real copyright issues.
This would be what Slev already listed:

Fimir
The *design* of the gargoyle
two maps
The name Karak Varn
Skaven, if using the material from White Dwarf
Some art

It would not include the dwarven halls and the elemental schools of magic. While this is original Warhammer background, it is also very generic and used in many other fictional worlds, too (think of Moria).
As an alternative name for Fimir, "Fomor" would be the logical choice, as Fimir are clearly inspired by them.