Introduction
This deck was first created in an attempt to adapt my modern 'robots' deck into the commander format as I stopped playing modern and started playing commander. A lot of the original direction of this deck came from the 2014 mono-red pre-con commander deck. Some elements of that deck still survive in this one but I've taken the edge out of it as no one wants to play against infinite combo Nevinyrral's Disk, Mycosynth Lattice & Darksteel Forge.
The Commander - Mairsil, The Pretender
Mairsil, The Pretender makes for some great graveyard recursion. He allows you to get some value out of the cards that maybe didn't even make it to the battlefield. Often there will be cards like Metalworker that either don't make it to the battlefield or get killed before I can use them. Mairsil, the Pretender gives you a chance to use some of these cards. The cards exiled with a cage counter on them remain that way for the game (provided your opponents can't return exiled cards) and that gives you constant access to certain cards you lost.
The Bombs
These cards are the ones you want to be tutoring for and the ones your opponents really should be removing as soon as they hit the board. The big name card here is Planar Bridge as it allows you to get everything else in the deck. A common late-game turn for this deck is to tutor out the bridge and then spend to go and fetch something else.
Metalworker - I still don't understand why this card was unbanned. It's beyond stupid. It can lead to some really ridiculous circumstances if it can survive. That last part is key as Metalworker will rarely survive the turn cycle if you can get it onto the battlefield. This card has provided me with an 8/8 Walking Ballista & a turn 3 Metalwork Colossus just to name a few.
Wurmcoil Engine - Wurmcoil is just a big beater that works nicely with things like Goblin Welder or any other sac outlet. Not only does it have great stats and replace itself but it can be a lightning rod for removal which allows you to play other bombs.
Hellkite Igniter - Can close out games by itself. With just a small mana investment this card can be hitting an opponent for 20+ each combat. More often than not you will be bringing out Igniter to finish someone off when they're tapped out with no blockers. It serves as a great backup win condition.
Hellkite Tyrant - This card has gotten significantly worse since the removal of Mycosynth Lattice from this deck but it's still good enough to run. Normally you will just be stealing other people's signets with him but he is another great back up win condition. If you can cheat it into play when you already have close to 20 artifacts then it should be easy to get the rest.
Steel Hellkite - This boyo can provide you with some nice board clear as well as consistent damage. The flexibility of this card allows it to fill whatever role you need it to. I find myself tutoring for it less and less recently as it does require a turn cycle to get online but when it gets going it's really good.
Metalwork Colossus - This card speaks for itself. It's a huge beater. It reduces its cost. It can come back.
Walking Ballista - If you can get a few counters onto this card then you get damage that can't be stopped. They wipe the board? Remove all counters and smack them in response. They try to destroy or exile the Ballista? Same again. They Voidslime or Disallow the ability? Just do it some more. Excellent card.
The Planeswalkers
I never used to enjoy using planeswalkers in my EDH decks and I didn't tend to use a lot of them. However, that's changed quite a bit now as I've realised how valuable planeswalkers actually are. I have considered running Tezzeret, Agent of Bolas in this deck but ultimately I opted not to.
Ugin, the Spirit Dragon - Ugin can be great for emptying the board of indestructible targets. His +1 abilitycan be really helpful and his ultimate speaks for itself. If you can get it off it can be really good.
Karn, Scion of Urza - New Karn provides this deck with some much-needed card advantage. He does this with his +1 ability. If you're playing the political game then you can ally yourself with someone to ensure you get the better of the two cards, but this rarely happens for me. Even though you normally get the worse of the two cards this ability is really powerful. It's worth it to use his -2 ability to create some protection for Karn. In this deck the token tend to be at least a 4/4 when it enters the battlefield.
Tezzeret the Schemer - I mainly use his -2 ability to remove dangerous targets. It gets around indestructibility very well and for 4 mana that's pretty good. The Etherium Cells can be handy if there are no targets on the board for him.
Tezzeret the Seeker - This Tezz is a great tutor. I will sometimes use his +1 in order to get some more counters on him so I can -X for 5 and get something like Kuldotha Forgemaster.
Daretti, Ingenious Iconoclast - Daretti doubles as removal and he creates blockers that protect him. His ultimate can potentially be game changing if you have the chance to get to it. He's a fairly recent addition to the deck so I haven't had the chance to use his ultimate yet but his -1 is plenty to justify his place in the list.
The Tutors
This deck relies heavily on tutors to get what it wants. Although, I have been implementing more card draw recently. Tutors are the backbone of the deck.
Fabricate - An all around good card in this deck. Seeing as the card goes into your hand it's a good idea to grab something like Walking Ballista or Hangarback Walker as they can't be fetched with Reshape or Whir of Invention
Whir of Invention - This is basically Chord of Calling for artifacts. As I said before, this mainly gets Planar Bridge but it's good for almost anything in the deck. I have used it before to fetch silly things like Temporal Aperture. It can also be used for to get an artifact land but this isn't a good idea unless you're really screwed. It's an instant which means it can be used in a pinch to grab a big blocker.
Reshape - This is a weaker version of Whir but it still serves a purpose.
Kuldotha Forgemaster - Great with token generation like Mishra's Self-Replicator as it allows you to start getting ridiculous. The main target for this is Planar Bridge
Diabolic Tutor - My other tutors specifically grab artifacts so it is a good idea to grab something like Karn, Scion of Urza with this.
Hoarding Dragon - This is a great tutor that gives you a silver lining against boardwipes. It also gives you a 4/4 body which is always nice.
Buried Alive - Used to set up some nice targets for Mairsil, the Pretender.
The aforementioned Planar Bridge & Tezzeret the Seeker also fall under this section.
The Removal
This deck lacked a lot of removal until recently. I find removal a fair way of keeping the game balanced. I don't really like a deck that runs loads of counterspells as it tends to ruin the experience for everyone else at the table. I find that removal is a great way to have enough interaction and control without stopping someone from playing.
Dreadbore & Hero's Downfall - The ability to remove a planeswalker is exceedingly helpful. Sometimes opponents will have a full board between you and their planeswalker that's a turn or two away from their ultimate. These two allow you to get around their board presence very nicely.
Terminate - Regeneration doesn't come up very often in my playgroup but terminate is still an amazing piece of removal.
Unlicensed Disintegration - In this deck you will 110% have an artifact out to trigger the built-in Lightning Bolt to the face on this card. If you don't... you're doing it wrong.
Crux of Fate - This list runs a few dragons so it makes sense to have a board wipe that will occasionally leave me with some of my board.
The Mairsil Targets
Mairsil can target a lot of cards in this deck with his ability and it will nearly always come down to what's in your hand and the graveyard at the time of casting him. Some of the ideal targets for him are as follows:
Goblin Welder - Recursion
Metalworker - Lots of ramp
Master Transmuter - Cheating things into play
AEtherling - Lots of great abilities & protection for Mairsil
Arcbound Ravager - Gives you the chance to pump Mairsil and turn him into a beater.
Hellkite Igniter - Commander damage, turns him into a huge beater, can probably close the game out better than the Igniter can by itself.
Kuldotha Forgemaster & Planar Bridge - Do I even need to say why these are good targets?
Steel Hellkite - Allows you to pump him up and means you can remove stuff with him as well.
Walking Ballista - You can put counters on him and remove them to kill shit. This paired with an exiled Arcbound Ravager can get a bit stupid.