Yorion, Sky Nomad made possible the rise of a different kind of deck to the meta: the 80-card extravaganza. Unlike previous attempts at a nonstandard ammount of cards in a deck (remember Battle of Wits 250 jank decks?), Yorion decks are competitive all across the board: there are Yorion decks in Standard, Pioneer, Modern, and I even saw a streamer playing Legacy versions. The fact is, having a bigger deck means you can fit in more of your favorite cards; the being paired with an advantageous mechanic (Companion) means that we can safely say "screw statistics". It helps the fact that Yorion is such a good card: decent 4/5 flyer that can blink all of our nonland permanents to retrigger ETB effects, reset planeswalker loyalties, and such.

Besides, why have a 7-card hand when you can have 8?

Like I said, there are all sorts of cool experimentations being done with companions in general, but Yorion in particular, and it all sounds pretty great. There are Yorion Jeskai Fires decks, and Yorion Azorius Blink decks, Yorion Esper Control decks... so I want to to throw in my two cents and experiment with Abzan Yorion.

Ikoria brought some nice tools to the Abzan color pie - notably Eerie Ultimatum, one of (if not outright the) best of the new Ultimatum cards. The new Vivien, Monsters' Advocate is a pretty solid planeswalker for creature-focused decks, Mythos of Nethroi is the best single-target removal in the current Standard, and so on. But I feel like the normal midrange versions kinda lack the abuse factor that other decks in the format have. Yorion is an attempt to address that by creating a grindier version of a midrange/control deck. I'm still testing how it performs, but preliminary results look promising enough.

The Deck

I was tempted to do an Abzan Doom version of this deck (with Lurrus of the Dream Den as a non-companion to recur the sacrificed eggs, but ultimately I decided to do an extension of MTG_Joe's Abzan Legends deck.

Charming Prince: So good for a 2 mana drop. The ETB effect is very versatile, and while you're usually going to opt for the scry 2, don't subestimate the gain 3 life option (Treacherous Blessing will sometimes drain you very low), and the "exile another creature until EOT" option can create some loopy interactions with Yorion (see the section on that for details).

Paradise Druid: Mana fixing, simple enough. Doesn't play that well with Cry of the Carnarium, but it's a mana dork with hexproof. Enables Kenrith to activate his off-color abilities, which can be relevant some time (the "1 mana: gain haste and trample" can sometimes finish off games on the spot and it goes over pesky Cauldron Familiar + Witch's Oven blocks).

Agonizing Remorse: It's our 2-mana Thoughtseize, but it compensates the extra mana by draining your 1 less and exiling the card from the hand (or, later on, you can exile something from the graveyward instead, so it's seldom useless later on like other discard spells).

Mythos of Nethroi: I said it's the best single-target removal in the format, didn't I? Normally it's a better Murder due to the single black in the mana cost, but if you need so and can spare the WBG mana composition, it's almost as good as Vindicate.

Ashiok, Dream Render: Graveyards are a big deal in the current meta, beween other BG and Abzan decks using it, Zenith Flare cycling decks trying to straight burn you up using it, and the usual Escape shanenigans with Uro, Kroxis and gang. Ashiok does get rid of their graveyard while potentially filling ours with our own stuff we may want to revive later. And on locked games, we could theoretically mill our opponent out by bringing Ashiok back one or two times.

Kethis, the Hidden Hand: Allows replaying legendary spells from the graveyard, while also discounting their mana cost by 1. Usually you don't want to play Kethis before you really can activate his ability, unless you're facing aggro (where his 3 mana 3/4 body is respectable) or to "ramp" into a better legendary spell.

Oath of Kaya: Off-color Lightining Helix on a legendary permanent with an ETB effect, which is perfect for our goals. Yorion can blink it for another shot, Vraska can sacrifice it for card draw, and Kethis can exile it from the graveyard to activae his ability. Sometimes it can even be played/replayed from the graveyard itself to deal damage to the face and close the game. Against mono-red, it's the best removal you can draw.

Treacherous Blessing: 3 mana draw 3 is decent enough, but how about blinking it with Yorion for more card drawing goodness? Unfortunately it drains us for 1 every time we cast a spell, and unlike Doom Foretold decks, we don't have a lot of ways of getting rid of it (basically sacrifice it for Vraska or target it with Mythos of Nethroi). That said, we do have some ways of gaining life to offset the cost.

Vraska, Golgari Queen: All in all, onde of the best planeswalkers for the current meta. Earlier on, she will usually be used as a 4 mana removal (specially good against 3 mana planeswalkers), but later on she can convert spare permanents into life and card advantage. "Spare permanents" usually mean creature tokens, but it also can be extra lands we've drawing, Paradise Druids we don't need anymore, and Oath of Kaya and Treacherous Blessings. We can also sacrifice spent permanents (like abother planeswalker with low loyalty or a 1/1 Polukranos) to send ti to the graveyward and possibly replay it at full force with Kethis/Elspeth Conquers Death/Eerie Ultimatum. And her ultimate allows you to win the game with a single point of combat damage, no questions asked.

Questing Beast: The planeswalker eating machine. Makes Teferi and Narset's life particularly miserable, but it also allows you to race aggro (due to the haste/vigilance combo) and block big stuff (due to the deathtouch ability). Against control or midrange, it sometimes wins the game on the spot.

Polukranos, Unchained: 4 mana for a 6/6 that cannot be destroyed by Heartless Act is already good on its own, but it can also be acticated to fight anbother creature (usually killing it). Sure, it becomes worse after taking damage, but when it finally goes to the graveyard, you can escape it as a gynormous 12/12 beater! It requires exiling 6 cards from the graveyard, however, so keep in mind this doesn't play nice with Kethis of Eerie Ultimatum. Also remember that Yorion can reset Polukranos's counters by blinking it.

Acolyte of Affliction: Basically this guy draws us a permanent card by milling us for 2 then returning it. Because of the desirable mill effect and the better casting cost, he's preferable in this deck over the better-stated Golgari Findbroker.

Vivien, Monsters' Advocate: She has an abysmal starting loyalty for a 5 mana planeswalker, but her effects all compensate for it. Creating a 3/3 Beast with your choice of vigilance, trample or reach is good already, but you also Future Sight your deck and can even play creatures from the top of the library! And while we don't really abuse her -2 ability, playing a 5 mana creature and getting for free a Polukranos or Questing Beast seems a good enough deal.

Elspeth Conquers Death: Of course, another one of the best removals in the current meta. As it is a saga, if Yorion blinks it before the last chapter, it resets to chapter 1 so you can exile another of your opponent's permanents. And we have so many nice things to bring back from the grave!

Tolsimir, Friend to Wolves: At first glance, Tolsimir doesn't seem that good in this deck: the wolf token is legendary so blinking it doesn't help that much, and without other wolves, his triggered ability seems very meh. But remember you also gain 3 life and it synergizes with Garruk's +0 ability.

Nethroi, Apex of Death: By itself, a decent 5 mana 5/5 deathtouch lifelink body. But he really shines on mutating - bringing up to 10 power worth of creatures back from the graveyward is, of course, almost like a mini Eerie Ultimatum.

Kenrith, the Returned King: The Big Man himself is a pretty good threat, as always. With Paradise Druid, we can potentially use any of his abilities, although the Abzan colored ones are pretty decent.

Garruk, Cursed Huntsman: Garruk can quickly close games by overwhelming the opponent with Wolf tokens (which trigger Tolsimir's ability). If you manage to generate his emblem, then any creature you play becomes a trampling giant that can also quickly finish the game.

Eerie Ultimatum: The ultimate bomb. Bring back one of every permanent in your have in your graveyward! A decently-fueled Ultimatum will usually cause a concession on the spot. This card is bonkers.

Landbase

33 lards are equivalent to 25 lands on a 60-card deck, which is reasonable considering we do have the Paradise Druids to help with mana. I'm running two Castle Locthwain because it's the best of the Eldraine Castles, and I think we have enough Swamps to support them. One Castle Ardenvale because sometimes generating the Human tokens is necessary as a sacrifice outlet to Vraska.

Sideboard

I'm still experimenting with the sideboard, but these are my current options. Keep in mind sideboarding 1 or 2 cards onn 80-card deck is less than ideal, since the cances of you actually drawing those cards are smaller, and we don't have the luxury of wishing something as a toolbox (like blue-based Yorion decks have the luxury of doing). But it's still important!

Grafdigger's Cage: At first it seems completely at odds with the theme of our deck, and it kinda is. However there's no other real way of stopping Winota or Gyruda decks (well, there's Hushbringer, but that'd be even worse for us). Ot usually replaces Kethis and Nethroi, of course. Keep in mind Acolyte of Affilictions still works (since it sends the card to your hand), and so does Elspeth Conquers Death and Eerie Ultimatum whem return anything that isn't a creature. On the other hand, it does stop the "cast creature from the top of the library" clause from Vivien (you can still look at the top card of the library, though).

Ashiok, Dream Render: Some decks require more intervention at their graveyards, so I have a third Ashiok to help with that.

The Wanderer: Now this is a card I'd never think I'd ever sideboard. However, she proves to be really versatile: in matchups against the Zenith Flare cycling decks, she provides shielding against the namesake spell (at least for one casting of it!), and against the various UG "ramp into big stuff" strategies, she provides renewable exile (that's important against the likes of Cavalier of Thorns and Uro, Titan of Nature's Wrath). All and all, a pretty solid choice.

Cry of the Carnarium: Hekps a lot with slowing Mono-Red down, and cripples Lurrus of the Dream Den. Could be Sthatter the Sky of Kaya's Wrath, but I'm still holding to the Cry as it is a bit faster against very fast starts.

Heartless Act: Complementary single-target removal to be used against decks that revolve around fewer creatures. Sometimes it can catch a Gyruda deck out of guard if all they get into the graveyard is a Spark Double or Thassa, Deep-Dwelling - but you need to get into full-control mode to get the exact timing to remove Gyruda, or else it won't work.

Shifting Ceratops: Put's a clock on control decks, cannot be bounced by Teferi or Petty Theft, and it can even be used to keep Dream Trawlers at bay.

Yorion and the Prince Interactions

Both Yorion, Sky Nomad and Charming Prince have similar ETB effects: exile stuff until the next end step, then it all gets back. Of course, that means one can exile the other, creating a loop that happens at the end step of every turn (yours, then the opponent's). And since Yorion can exile multiple things at once, that means you can get extreme value of whatever you have with ETB effects in your side of the field.

It works like this: Yorion enters the battlefield, it exiles everything you want. If that includes Chaming Prince, when he comes back at the end of your turn, his ETB effect is triggered, so you can pick the "exile another creature" effect and exile Yorion. On your opponent's end step, Yorion comes back, so you can exile everuthin you want again - and if that includes Charming Prince, you redo the entire proccess at the end of your next turn. Whatever is exiled by Yorion alongside Charming Prince triigers its ETB effect again.

The nice thing is, since Yorion exiles permaments, not only creatures, you can replace some of the stuff in the deck with other creatures, artifacts and enchantments that have ETB effects to get even more value. Hell, you could even have a bunch of planeswalkers with only minus abilities and "refresh" them with Yorion. That's a way for you to mill the opponent with Ashiok, or get a lot of milleage of The Wanderer, for example.

One last thing you can do with Yorion: if you do the cycle with Yorion entering the battlefield on the end of your opponent's turn, you can remove Treacherous Blessing from your board on your turn, so you can actually cast spells without losing life (and refilling your hand at the end of the turn). It's an useful interaction to keep in mind when dealing with multiple copies of it and/or being at low life.

Vivien Tutoring

The -2 ability on Viven allows you to "cascade" when casting a creature spell, except it's better than the Cascade ability because you tutor for the second creature. Obviously, the normal use for this is so you can immeadiately start the Yorion-Prince cycle by casting Yorion and searching for Charming Prince, but keep in mind other useful targets for tutoring, such as Acolyte of Affliction to immediately recover something from the graveyard, or Questing Beast to push for immediate damage. In fact, a Questing Beast attack plus an Oath of Kaya blink pushes for 7 points of damage at once - on an Abzan deck, that's not very usual, so your opponent may be caught off-guard with low life points thinking you can't possibly finish him off in one turn.