Chromium, The Mutable
About the deck
Chromium is a solid control deck finisher and will generally be your win condition and can usually do fine without any additional equipment or support (although Duelist's Heritage certainly doesn't hurt). By having your primary win condition in the command zone, this frees up spots in the 99 for more interactive pieces. Generally you wait until you are ready to start swinging, flash it in right before your own turn and then just go after whoever is the most threatening at the time. Chromium is fairly difficult for opponents to remove without using a board wipe unless you have no cards left in hand. There is no need to rush into battle with Chromium, the deck packs a decent amount of interactive elements and recursion to buy you time until you are ready.
I'm constantly messing to some degree with the "Miscellaneous Instants" and "Creatures" sections just to try new oddball things out but most of the rest stays fairly stable. Various fog effects, theft effects, Exsanguinate, and other things have been in the mix at various times.
One thing that probably stands out is that it is a deck with blue that has no counterspells. This is a conscious choice just to free up space for other fun/jank. Clearly this deck could be adapted to run counterspells if one wanted to but I find this more fun (totally not opposed to them at all and have plenty in other decks, it just doesn't fit my vision for this particular deck for me). It probably wouldn't be difficult to find room for 4 or 5 counterspells if you really wanted them.
There are definite synergies with cards like Horobi, Death's Wail and Dismiss into Dream with the various targeting cards like Dauthi Embrace. This has been a constant since the decks inception. Cowardice is a card I keep meaning to put in but have never gotten around to trying, mainly just because finding a space for another higher CMC card is tricky.
Cards like Duelist's Heritage and Dauthi Embrace are great political tools that can help you help others push through their damage. Promising to give an opponent's biggest creature double strike if they swing at someone who isn't you can be a great incentive and the potential to make their creatures basically unblockable is great as well. These two cards immediately become very different once you get Horobi, Death's Wail, Willbreaker, or Dismiss into Dream into play.