4 Hermit Druid
8 Combo Pieces
4 Narcomoeba
1 Dread Return
1 Sutured Ghoul
1 Lord of Extinction
1 Dragon Breath
7 Fixing and Finding
4 Sleight of Hand
3 Night's Whisper
12 Protection/Disruption
4 Force of Will
3 Duress
2 Cabal Therapy
3 Repeal [Bounces tormod's crypt, pithing needle, relic, etc.]
9 Broken
1 Ancestral Recall
1 Brainstorm
1 Ponder
1 Time Walk
1 Demonic Tutor
1 Vampiric Tutor
1 Imperial Seal
1 Tinker
1 Darksteel Colossus
20 Mana
7 Fetches
2 Bayou
2 Trop
2 U. Sea
5 Moxen
1 Lotus
1 Pendelhaven (yes, and it's awesome - saves druid from darkblast and, once in awhile makes relevantly large narcomoebas)
2. How the combo works
The combo works so that, if you activate hermit druid, you win that turn.
1. Activate hermit druid during your first main phase
2. Mill your entire library, putting into play up to 4 Narcomoebas (and you need to bring in at least 2)
3. Sacrifice Narcos/Hermit to Cabal Therapy EITHER (a) your opponent, to get any counters out of their hand OR (b) yourself, to drop any combo pieces you drew into the yard
4. Sacrifice Narcos/Hermit to Dread Return a Sutured Ghoul. Remove Lord of Extinction to Sutured Ghoul, and attach Dragon Breath. You now have a hasty trampling dude with power and toughness both at around 40-70.
5. Attack with super gigantic sutured ghoul lord of extinction hybrid fatty dude
As you can see, this is very fast and simple. If you mull to three, and those three cards are land, mox, hermit druid, then you are going to have a turn 2 win. Hermit Druid is a 1-card combo for 2 mana, which is practically unheard of.
The presence of DSC in the deck buys you a turn if anything goes wrong, gives you an alternate win (in addition to hard-casting an enormous lord of extinction), and makes sure you have the auto-win against an un-suspecting painter/grindstone type.
3. Comparison to Oath of Druids
The easiest comparison for hermit druid is to oath. They both have the word druid in there, both cost 1G, and both take advantage of milling yourself.
Pros: Hermit Druid is much faster than Oath, since the first turn you get after casting him you can win. Also, Hermit Druid doesn't require having a forbidden orchard in order to work. These in concert make HD a much much faster kill condition than oath of druids
Cons: Hermit Druid is much more susceptible to hate, and takes up a couple more slots. Essentially, he is more fragile. But I think in the fast format we've got, the speed and ability to combo-off without a supporting orchard makes HD significantly better than oath.
4. Overall thoughts
First, the deck is surprisingly resilient to mana denial and good against shops. Because you only ever need to tap a total of 3 mana over 2 turns in order to work the combo, you can usually win even if you only get to use each of your lands once. Plus, you're completely null rod proof. In fact, I've played the deck with MD null rods quite a bit, since they shut down relic and t-crypt. Nothing in your combo is hampered by a null rod.
Second, the deck's main problem is post board games. It isn't in the bad situation that Ichorid is in because it has a full mana base and a ton of draw and tutors. You can play a Hermit Druid despite their yixlid jailer or whatnot, and use all the deck's resources to find something to bounce the jailer and win right away. But, the matchup does go down entering games 2 and 3. Honestly, I've still been working on the sideboard as well, and there are a few good options, but given the flux I expect the meta to be in, that probably isn't worth posting just yet.
That's enough for starters. Let me know if you have any questions or suggestions.