+1

This deck is awesome. Underworld Cerberus is very underrated, and his passive totally eliminates popular delve decks. I think Generator Servant is even more underrated, so I'm happy to see him in your deck.

My only suggestion is trading out for the 2x Hammer of Purphoros for 2x Alesha, Who Smiles at Death. As I see it, Generator Servant serves as your haste mechanism for Underworld Cerberus, and you can use Alesha, Who Smiles at Death to bring back Agent of Erebos or Generator Servant who are vital for your deck.

Also, you already have haste on Shaman of the Great Hunt, Stormbreath Dragon, and Vaultbreaker.

That is excellent feedback, the Hammers ARE gratuitous - and I'd even taken them out, doubted myself, and put them back in.
I was thinking about Alesha, but it seems that she would be best placed in her own deck - with Goblin Rabblemaster, Battle Brawler, Brutal Hordechief and Mardu Hordechief

It just seems that she would be a little underwhelming with the targets available to her - Agent of Erebos for the ETB effect or Battle Brawler are the best available in this shell. Perhaps a Whip of Erebos and more removal instead or an 8th 2-drop?

Good points about Alesha, Who Smiles at Death. After reading your thoughts, I also realized that her mechanic doesn't work at all since Underworld Cerberus doesn't allow you to target cards in your graveyard. So on that same note, I would avoid Whip of Erebos.

I think your best bet is including removal to help eliminate early game threats like Savage Knuckleblade, Polukranos, World Eater, and Anafenza, the Foremost. maybe 2x Hero's Downfall, if you have em?

Derf. I knew the issue with Alesha/Undeworld... and went and added one whip anyway. :/

I'll keep the Vaultbreaker in side and put in 2 Hero's Downfall-- Vaultbreaker is really a combo-maker, but only if I have a 4 drop in hand and a Cerb for T5 and no Generator Servants and a big guy I want to pitch rather than cast... so he's toast.