Good Fiery Boy

For this questline you need to be on your Dark Iron Dwarf (lvl 50+) and currently it has to be the DID that did Heritage of the Dark Iron.
Use your Mole Machine to get there, it's in your general spell tab. Select Eastern Kingdoms > Shadowforge City.

1. 
   
2. The Anvil-Thane's Designs - turn around and walk forward, upstairs, follow the way on the right side (don't jump down) and enter the Grim Guzzler
3. 
   
4. Brawl or Brew - click her dialogue and select "brawl". Fight against [npc=26125]
5. 
   
6. It's Called Borrowing - go down and kill [npc=176995] for [item=184916]. Go back to the ramp where you came from and collect 5 [item=184915], they lie around in the big marked area near the [npc=144132]s. Follow the way until you reach Kasea Angerforge and ask her for the [item=184917]. Turn around and go back a bit to turn in the quest
7. 
   
8. Weapons o' the Dark Iron - talk to [npc=144154] and click the darkforged ingot
   Turn in and get [item=184922].
9. 
   
10. Delivery for Kasea - follow the way back
11. 
    
12. Good Fiery Boy - click [npc=185352] next to you, throw it on the ground and click [npc=185305] to pet him. Collect 4 [item=190606] from the boxes and feed him. After that, click the extra action button [spell=367727].
    Turn in and get [item=191123].
13. 
    

Questline took about 15 minutes with level 52 and ilvl 85.

I just completed this quest line on my level 60 faction changed Dark Iron dwarf hunter. So if there WAS a requirement to complete it on a toon you had leveled from 1 - 45 for heritage that seems to be gone. I have completed the heritage lvling, just not on the toon I completed this on.

I only had one Dark Iron Dwarf, and for some reason, they weren't valid for the Heritage quests or this quest. Rather than worry about it, I leveled a new Dark Iron Dwarf, doing zones I hadn't done on a plate wearer, and got a lot of nice transmogs along the way.

And now I have my Flame Woof and the Heritage Armor and weapons. Good times.