I have the exact same issue. Defeated the Dread Lords and have 100% victory, but the game won't end. I defeated the Drengin and Yor as well, with the same result.

I experienced this as well. I decided to investigate further in cheat mode, and the chapter only ended if I killed off EVERYONE, teammates included.

Same issue. Read somewhere else that the end condition race to kill is a race not even in the map... Patch please!!!!

You can fix it with the scenario editor:

Just click on the "Editors" button on the Twilight launch menu, then select "File" and "open."

You need to find the install directory for GalCiv2. On my install, it's:

C:\Program Files (x86)\Stardock Games\GalCiv2

I suspect the install directory will probably be for most people:

C:\Program Files\Stardock\GalCiv2 or C:\Program Files\Stardock Games\GalCiv2

You can also right click Twilight of the Arnor in Impulse\My Games and select "Open installation folder."

Note: It is not the GalCiv subdirectory under My Documents\My Games.

Once you locate the GalCiv2 directory, you need to go into:

Twilight\Data\English\Campaigns\DreadLords

Open Apocalypse.gc2scenario

Select the "Win/Lose Events" tab

Select "Defeat the Dread Lords"

Click "Edit"

The "Race Elimination" button should already be selected, but it will say "If Krynn are eliminated, then victory"

Switch the first dropdown menu so that instead of "Krynn" it says "Dread Lords".