What is all this noise about a supposed fourth dragon, an undead one no less hidden somewhere in the graveyard district?

If someone has found it, could you please be so kind as to let me in on the location. I have ground everything else that moves under my bootheel and I am quite keen to pay this beast the same respects.

There's no undead dragon. Also, there are FIVE dragons in the game, not 4. (not including fairy dragons and such.)

You serious mate? 5 !!!!!!
What did I miss?

There's big red, the shadow dragon, the silver dragon, the black dragon in chapter seven and the dragon in the endgame.

Umm... Firkraag, Shadow Dragon, Lair' Nizard... bah! Adalon and... i forgot...

I forgot the end Game... daym...

The GREEN Dragon
but i didn't remember that in the beginning had to think long and hard before i did
becoz you don't have to fight him and he isn't really of any importance if you don't fight him
so we've got
the achient Red
the weak Shadow
the good Silver
the greedy black
and the fair Green dragon
which one did you think was strongest?
i though Firkraag to be the toughest

ehm Angel

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if you want to find the 4th dragon he;s where they are
Shadow Dragon - Umer Hills when going to the Shade lord
Red Dragon in Windspear hills
Silver Dragon in the underdark
Black Dragon in Suldererefsdrern or something
Green Dragon when collecting the tears