This scenario pits the players against the most powerful Nibelung clan warrior (likely the clan leader). It's a good fight to end a session on, cap off a dungeon romp, or encapsulate a larger story dealing with regional threats.
The PCs have climbed a staircase to reach the throne room of the Nibelung. It's lit, either from sunlight shining through cracked walls and windows or torches used to signify the room's importance to the clan.
The section immediately in front of the PCs' starting section is trapped. The first PC to enter the section triggers the trap and must make an Acrobatics roll vs. 1d8 or be covered in foul goop (-1 to all Stat Tracks).
0 0 0 0 0 0 0 0 0 0
This is a very straightforward sort of fight. The Champion will engage anyone that approaches it in melee (likely any Warrior and/or Brute present), while the Tossers are expected to exchange fire with ranged PCs. Tossers try to avoid well-armored PCs and prioritize any PC currently incanting.
Since the Champion can't trigger the trap, it's happy to lure melee players in by moving into the trapped section should it win initiative.
The PCs defeat the Nibelung. This might close out a part of your story with a regional threat eliminated, or it may be just the beginning of a deeper dungeon to delve. Regardless, PCs should be rewarded with treasure from the Nibelung's stash and potentially Karma as well.
The PCs are forced to retreat from the throne room, suffering an injury. If the battle was closely-fought, the Nibelung will flee rather than face the PCs again (taking any of their treasure with them). If the PCs were handily routed, the Nibelung will be over-confident and will not take any measures to improve defenses (other than resetting the trap in the exact same place it was before).
The default presentation of this scenario is fairly easy, appropriate for beginner players or those not especially well-equipped. With veteran players or those who have accumulated more Gear, you'll want to elevate the difficulty a few notches to take advantage of Nibelung properties otherwise ignored in this terrain.
The easiest tweak is to change the lighting to either shadowy or dark. This gives the nyblings substantial advantage with their Darkvision, limiting PC vision and requiring them to take up Gear slots with illumination devices.
Adding another goop trap or two could also prove useful, particularly since these enemies aren't really adept at lowering PC Stat Tracks. You might even add a lever that the Nibelung can use to reset goop traps, adding a new tactical dimension to things.
Height changes can also give advantage to the Nibelung. Elevate the northern row to 1 section above the rest of the battlefield, creating a balcony over the throne room. The Nibelung can freely climb this with their Height 1 property; however, PCs will need to succeed on an Acrobatics roll vs. 1d8 to cross. Failing this roll while attempting to cross upward results in no movement, but failing this roll while attempting to cross downward results in 1d6 falling damage (but the PC is able to move down).
You could also impose a penalty on any PC trying to fight from the staircase (their starting section) in order to encourage more movement. This is useful if you have several ranged PCs and want to keep them from just staying still the whole fight, particularly if you want the Tossers to be able to reach them without having to move southward. A simple penalty would be to note that PCs are treated as though all Stat Tracks are 1 lower while on the staircase.