Defenders. Very straight forward.
Update: This is hardly a proper Primer, but I think the deck doesn't need one. I have returned the Wall of Kelp combo with Axebane Guardian and Intruder Alarm. Most importantly, however, I have removed fringe use cards, that will simply not support the theme all of the time or simply give less value compared to the new inclusions.
From multiple rounds of play, the deck struggles most against constant removals. So I have included recursion and phasing and regeneration and hexproof, as well as tutors. This should increase the consistency of the deck and help me deal with board wipes. I also removed gimmicks like Meishin, the Mind Cage. The deck doesn't need these effects. If you look at the average decks for Arcades on EDHREC, whether you go for expensive budget or theme filter, you will find mostly the same inclusions. Everyone is playing these synergy cards that only give tiny, situational and very incremental boosts to your defender theme. But, as I already stated, they do nothing to recover from wraths or other kinds of removals. While you may end up with walls that are tougher and more threatening, you best be able to overrun all 3 of your other opponents FAST. I somehow doubt that this is feasible most of the times. I have stripped the popular build for this deck of all those small, incremental and highly situational cards (like +1 toughness for all untapped walls, or +1 toughness for each guild gate, et cetera) and only kept the ones that give an advantage that matters. Then I replaced all the exclusions with ways to recover from or protect against removal.
So this is how the deck plays:
Get out Arcades as soon as you can. Play walls. Protect Arcades as soon as you can. Draw cards. Prepare a hand that can deal with removal by either recurring the creatures out of the grave yard, regenerating them or phasing them out. Start stomping your opponents. Arcades is very straight forward. Aggro and card draw. But once he is removed, you are a sitting duck. So instead of trying to put every possible toughness booster or vigilance effect into the deck, one should really put quite an emphasis on the ability to re-build a board state after a wipe - because it WILL happen.
As most of the decks functions are obvious, I will only highlight some cards that will help you stay protected or help you to recover:
Eerie Interlude - I think this is better than Teferi's Protection because it trigger Arcades' card draw ability. Phasing wouldn't allow that. I would still include it, though. But I have no space left in the deck.
Creeping Renaissance - Choose Creatures. There you go. And it has flashback.
Asceticism - Together with Overgrown Battlement or Axebane Guardian, this card is an obvious inclusion. Add Seedborn Muse and you will never be caught unprepared.
All of the above can be Tutored. And that is as good as it gets. You can, of course, try to optimize with more on-theme cards. But I think it will again come at the cost of protection and recursion.
Update 2: Drift of Phantasms - I HAVE to find space for this. It tutors Axebane Guardian, 2 of my wrath effects, Eerie Interlude, one of my card draw defenders, and Intruder Alarm. Axebane and Alarm are already powerful when on the battlefield together, and an endless combo if you can cast Wall of Kelp. But the synergies don't stop here: We can recur it twice (for a total of 3 uses!!) with Creeping Renaissance or even bounce it to use its Transmute ability later in the game with Jeskai Barricade. A clear inclusion. I am thinking of including it in place of Gatecreeper Vine. The land tutoring is great, but the card only has half value since I have removed the Guildgates from the deck.
Update 2: Deck is now properly out of the Theory Zone. Tested it in my weekly EDH group. 4 player game. The deck very consistently does what I intended it to do. The amount of defender creatures is just enough to constantly draw one. The mana base is solid and I am drawing a good mix of lands. The tutors pulled out all the key cards I needed and I even got to use Asceticism and Creeping Renaissance to protect or recover. Axebane Guardian did a lot of the heavy lifting. For my final attack, one of my opponents tried to Plowshare Arcades. I Mizzium Skin around it and struck for lethal. The game worked out exactly as described in the game-plan for the deck. I didn't, however, top-deck enough tutors to quickly get the Wall of Kelp combo going. So that is the only thing left the deck has to demonstrate.
This deck had to contend against a super aggressive Ezuri Elfball deck, Atraxa and Sigarda. 2 board wipes that excluded my defenders and a Cyclonic Rift later, I put myself in a position where I just dealt too much damage too quickly for anyone to recover their board state properly. Tetsuko Umezawa, Fugitive and Stalwart Shield-Bearers made sure I romped around the battlefield properly. This is a super fun, casual aggro build. It would probably struggle against really high-powered deck lists with tons of stax and prison effects, but I guess that can be said for most casual decks. I don't think Arcades could ever be built in a truly competitive way, since the entire deck's functionality relies on him alone. Without him, all I can do is defend. But I would not be able to execute any win condition. Not a good prerequisite for competitive play. That said, this Arcades build is the most fun I had with EDH in a long time.
