Dr. Dagsson and the Artifacts of Madness (EDH / Commander)

I hate Sheldon for killing you.

Step 1: Play and secure Arcum Dagsson

Dbag commander indeed! Anyone who's played against Arcum Dagsson before will recognize his power and his threat to the table as soon as you identify him as your commander and place him in the command zone. Unless the table is something like Arcum, Sharuum, Zur, and Prossh, you're going to be the one that people hate the most. Never play Arcum without something to back him up unless you got a crazy starting hand and are casting him on like T1 when your opponents are tapped out. Barring that, you have 3 options to keep the old geezer safe:

Cast Arcum and immediately equip a shroud-granting artifact.
Cast Arcum with haste and an artifact creature already on the field and immediately tutor for Lightning Greaves.
Cast Arcum with neither haste nor shroud and defend him until your next turn with countermagic (avoid if possible, especially in games with 3+ opponents).

Ideally, you want to drop a mana dork turn 2 to ramp into Arcum turn 3 and either give him shroud immediately or give him haste and use his ability (saccing the mana dork) to fetch him shroud. If, while you do all this, you still have some mana open and cards in hand to Counterspell your opponents' stuff, that's even better.

Step 2: Create an engine

By this time you will probably have exhausted most of your opening hand just to play Arcum and secure him on the battlefield. But the game's just begun--you still need to assemble your game-winning combo (see step 3) to win. In order to kick out your game-winning combo, you need an engine, a repeatable method of gaining resources. With any luck I will still have some cheap artifact dorks in my hand, but often I won't, and in those scenarios I will often use Arcum's first tap to fetch Myr Turbine.

The turbine and Arcum together form the simplest engine in the deck; as you go into goldfish mode, the Turbine ensures you can tutor for any noncreature artifact at least once on each of your turns, no matter what you topdeck. Additionally, as you'll soon read, the Turbine is a cornerstone of many of our strongest combos and interactions; as long as it's on the field, we can seamlessly transition between our main and secondary strategies as necessary.

With turbine + Arcum alone, you can successfully win the game in at most 3 more turns, which for many casual-oriented players might already might seem like a pretty short clock...but in competitive play, it's not quite short enough. Your opponents will still have plenty of time to come up with a solution--Return to Dust, perhaps, or Toxic Deluge to wipe your board...heavens forbid they play Null Rod!

Instead, the overarching goal is use Arcum and your dorks in addition to whatever tutors you draw in your hand (Transmute Artifact, Fabricate, and so forth) to assemble the following combo, which is much faster:

Rings of Brighthearth + Basalt Monolith + Staff of Domination

This combo only requires 2 Arcum activations to assemble, half as many turns needed as turbine + Arcum alone. Tutor for Rings first, then sacrificing two dorks at once you can tutor for the monolith and staff at the same time by copying Arcum's activation ability with the rings.

Note that this entire combo can be deployed and executed at instant speed--not only can you combo off on your opponents' turn, but you can keep comboing off in response to a removal spell. For example, if, in response to one of your activated abilities during your combo, your opponent casts Naturalize targeting Rings of Brighthearth, you can simply keep on producing infinite mana and drawing your deck in response. By the time that Naturalize reaches the top of the stack, you'll have already won the game or else drawn into something to counter it. In summary, only effects which freeze the stack, such as Split Second cards like Krosan Grip and Wipe Away, can stop this combo once it gets started.

Worthy of note is that for several years prior to April 2013, Sheldon and the EDH rules committee had Staff of Domination on the EDH banlist. Any veteran EDH player will tell you, though, that Arcum had been a top-tier commander long before Staff's unbanning. Prior to April 2013 we used Sensei's Divining Top as the draw component in the engine, such that the combo looked like this:

Rings of Brighthearth + Basalt Monolith + Sensei's Divining Top

Note that the Top engine suffers from one critical flaw: one of the steps in the combo to draw infinite cards is hardcasting and resolving Top for each card drawn, which can only be done at sorcery speed. So, building on the example I gave earlier, if in response to one of your Top hardcasts, one of your opponents casts Disenchant targeting Rings of Brighthearth, you cannot simply keep drawing cards in response: Disenchant resolves first, your Rings are destroyed, your engine is thwarted, all while Top is stuck on the stack. This is why Staff, which evades this pitfall, has supplanted Top as our go-to draw component for our primary engine.

Of course we still run Sensei's Divining Top in our Arcum decklists nowadays, because it's such a great card on its own for manipulating topdecks and we'd never cut it for anything, so this older combo is still wholly valid and usable today. Indeed, in some ways it's even easier to deploy than Rings/Monolith/Staff because Top is just 1 cmc and can therefore be tutored for and played more easily through non-Arcum methods. If you don't suspect instant-speed removal will be a problem, or you don't plan on comboing off on an opponent's turn, or perhaps your Staff of Domination simply gets removed, always remember that you can fall back to the classic Rings/Monolith/Top engine that Arcum decks have relied on for many years prior to April 2013.
So Rings + Monolith + Staff (or Rings + Monolith + Top) already has the deck down to a "two-tap clock," so to speak--two Arcum taps is game over.

Myr Turbine + Clock of Omens + Mycosynth Lattice

The good news, as with the previous engine, is that each card, on its own, is already exceedingly useful to us in a myriad of other ways (particularly Myr Turbine as I mentioned earlier), so you're never "wasting" a tutor or running into a dead draw as you assemble these artifacts. Unlike the Rings/Monolith/Staff combo, though, this engine requires some manipulation and foresight to work properly.

Firstly, Arcum Dagsson can't have Shroud. This is vitally important. If you're planning on using this engine, choose Swiftfoot Boots as your protective equip of choice, or be ready to leave Arcum vulnerable for the duration of the combo.

Then, you'll probably want to tutor out Myr Turbine after playing Clock of Omens and attempt to use them and your mana to create as many permanents on your side of the field as possible. Lastly, on your combo turn, you'll search out Mycosynth Lattice. With sufficient untapped permanents (all of which are now artifacts), you can use Clock of Omens's ability to repeatedly untap Arcum and tutor out a few cards at instant speed: Basalt Monolith and Rings of Brighthearth. Now you're ready to combo.

Rings + Basalt gives you infinite mana as described above. Go ahead and generate a bunch.
Tap Basalt and any other untapped permanent--we'll call it Permanent X; it could even be Clock itself--to activate Clock of Omens' ability. Copy Clock's ability with Rings by paying 2.
Use one copy of Clock's ability to untap a permanent of your choice (for example, Arcum) and the other copy to untap Permanent X.
Untap Basalt by paying 3. Now the engine is fully reloaded, and the cycle can begin anew.
You can now untap your entire board at will, repeatedly activating at instant speed any permanent of your choice, including Arcum himself for infinite tutors, Staff of Domination for infinite draw/infinite life, Myr Turbine for infinite tokens, Null Brooch for infinite countermagic, and so forth.

In the event that Rings of Brighthearth is exiled, you can still use a Clock-based engine to combo off, although it becomes slightly more difficult to do so as you'll require some more preparation. There are two possibilities to do so, each with different setups.

Possibility #1: The setup for this one is that you will need to create a source of infinite mana beforehand. As explained later in this primer, this will most likely end up being Power Artifact enchanted on a monolith. Instead of tutoring up Rings and Basalt to start the combo, instead tutor up both monoliths (or whichever one you don't have out already): Basalt Monolith and Grim Monolith.

Generate a bunch of mana from your pre-assembled infinite mana combo.
Basalt Monolith and Grim Monolith can be repeatedly untapped by spending that mana to fuel Clock of Omens infinitely.
With Mycosynth Lattice, you can once again untap your entire board at will, most importantly Arcum for infinite tutors.

Possibility #2: This is by far the most fragile of the Clock combos as it requires the most pieces, but we already run all the cards for it anyway as part of our other combos so I feel it's worth a mention. The setup for this one is that you need two copies of Staff of Domination on your side of the field, and an artifact that taps for 3 or more. This means you'll first need to stick Staff of Domination and then copy it, preferably in the same exact turn so as to minimize your opponents' opportunity to react. There are three efficient copy effects available to Arcum; my list runs two mainboard and one sideboard: Copy Artifact, Phyrexian Metamorph, and Sculpting Steel. Remember that only Sculpting Steel, as a noncreature artifact, is tutorable by Arcum. You'll also need an artifact that taps for 3 or more, which include Grim Monolith and Basalt Monolith (both of which, again, are already in our deck for their overall utility). If you can manage to get all of that set up without your opponents interfering, then the combo is simple:

Tap your mana-producing artifact (Grim Monolith or Basalt Monolith) for three mana.
Tap both copies of Staff of Domination to untap that mana-producing artifact via Clock of Omens' ability.
Use each staff's ability, "1: Untap Staff of Domination" to untap both staves by spending a total of 2.
Thus, together these cards become "Pay 2: Add 3 to your mana pool." This can be repeated infinitely for infinite mana, which can then be turned into infinite card draw, life, untaps, etc. through further use of Staff of Domination and Clock of Omens.

Now that your engine of choice is set up, all that's left to do is win.

Step 3: Win the game
In the past, the way we won was by using our engine of choice (usually Rings/Monolith/Staff, as Paradox didn't exist back then) to generate infinite mana, draw infinite cards, and assemble the following combo using the countermagic we drew along with the rest of our deck to ensure nothing goes wrong at this critical phase:

Darksteel Forge + Mycosynth Lattice + Nevinyrral's Disk

This combo effectively destroyed all permanents on the board except ours. It worked well because it didn't target anyone, so it couldn't be stopped by player shroud effects (like Grapeshot or Blue Sun's Zenith or Disciple of the Vault all could) and because it was indestructible.

But at the same time it had a major drawback: Darksteel Forge and Nevinyrral's Disk were almost always dead draws when they showed up in the hand. We never really cast them outside of the combo. And let's be honest--player shroud effects like Ivory Mask aren't all that common an issue to begin with. So, in the interest of streamlining, when Kaladesh came out, both of those cards were moved to the binder-board in place of:

Walking Ballista

Since we already had infinite mana by the time we got around to playing Forge/Disk/Lattice in the first place, we can now simply use infinite mana to cast Walking Ballista for x=1000 and ping everybody to death. Making that swap freed up 1 card slot, and it saves us from occasionally having to topdeck or mulligan into Darksteel Forge or Nevinyrral's Disk, which used to be one of the weakest and most frustrating things this deck could do.