Bottom Line Up Front (BLUF)

This Deck's primary plan is to flood the board with powerful token creatures that overwhelm our opponents (via Kiora Bests the Sea God & Chronozoa) with the secondary plan being to make large threats to kill our opponents via direct damage (via: Dark Depths, Gavel of the Righteous). Everything else is here to accelerate that strategy and i'll do my best to break down each section below. But first we'll go over some important interactions to understand for this deck.

Important Notes

1. Sagas

   2. Quicksilver Fountain

   Sagas are the most consistently fun part of this deck. during every upkeep, you put a lore counter on a saga, and the chapter ability that's associated with how many lore counters it has triggers and goes on the stack. Putting a lore counter on a saga at any other point will trigger the associated chapter ability (for example, if you put a lore counter on a saga that already has 1 during your main phase, when that counter move resolves the 2nd chapter will trigger and go on the stack). Removing a counter however will not trigger the previous chapter. BLUF: The only way to get the saga abilities to trigger are when counters are put on the saga. What's even more interesting however is how the final chapter of sagas work. Every time a saga is triggered and goes on the stack, after the trigger resolves state based actions check if the saga has 3 (or whatever its max chapter is) or more counters to sacrifice it. This state-based action check cannot be responded to (as is the nature of state-based actions) but the triggered ability CAN. This allows us to repeat final chapters without losing the saga! The easiest way to do this is to wait until a chapter gets it's final lore counter, and the final chapter ability goes on the stack. In response to that ability being on the stack (before it resolves) use an instant speed counter removal tool (most likely Goldberry) to remove one of it's lore counters. The triggered ability is already on the stack so it will resolve, and after it resolves the state-based actions will check and see that the saga doesn't have enough lore counters on it to be sacrificed so it will stay! You can continue to repeat this as long as you have ways to remove counters from the saga.

   This is one of my pet cards, but it works wonders in this deck and is always a card that people will ask to read a few times before they understand the true horror of what it can do. While in play, every player's upkeep that player has to put a flood counter on a non island land they control. The flood counter turns that land into JUST AN ISLAND this means their command tower that taps for any mana of their commander's identity? Nope. It just taps for blue now. Their field of the dead that keeps generating them zombies? just generates 1 blue and nothing else now. This card will slowly and surely make all your opponents only able to tap for blue mana on their lands. Once the lands of the board are nothing but islands, then all the flood counters go away, but with our ability to remove flood counters from our non-island lands, this should NEVER HAPPEN. "but i'll just remove quicksilver fountain" you hear your opponents say, and this is when you remind them that the flood counter effect is inherent to the flood counter, not the artifact, so just let them do it and when the fountain is gone you can inform them that their lands are now PERMANENTLY JUST ISLANDS (I mean, until they find a way to remove the flood counter).

Card Draw

We have important pieces to get to to include our sagas, so the card draw here is aimed at that. There are a few proliferate effects that we want to help generate counters for removal, and Jin-Gitaxias flips into a powerful saga, while The Bath Song can protect us from mill strategies (by repeating its final chapter as needed to keep our deck full). The Mirari Conjecture is a stretch to add to this section, but notably it will let us recycle instants and sorceries we have already cast so I left it here as sudo-card draw.

Tap/Untap

We have a greater proportion of these than other packages in the deck just due to how multiple uses of goldberry per turn not only directly helps our strategy of removing counters, but also draws us cards when Goldberry, River-Daughter moves them off of herself.

Ramp

This is a mostly standard ramp package for mono-blue, As Foretold and Pyramid of the Pantheon synergize with our proliferate effects, and Scroll of Isildur's first chapter can let us steal sol rings and other ramping artifacts our opponents cast. Since we can keep our sagas in play indefinitely, we'll never have to give them back! Urza's Saga does multiple things for us. 1. Its a saga we can take lore counters off of. 2. If we use the strategy to continue to retrigger the final chapter (described above) we can pull our Sol Ring and/or Pyramid of the Pantheon for ramp. As a win con however, we can use it's second chapter ability to begin pumping out constructs that get bigger with each one we make, and we have several untapping affects we can use on the saga to use it multiple times a turn. Optimally, you will use Snow-Covered Islands so in the case you get Extraplanar Lens out you aren't sharing the ramp with normal Island using players, but It's not something that's gonna be important every game, and I think there is much cooler art on some normal Islands, so up to you if being optimal is more important than finding cool Islands to play aesthetically.

Protection

Lets be honest with ourselves. We are playing Mono-Blue. In relation to our opponents our ramp is mediocre, and our creature board state will take a bit of time to become threatening, and before then a lot of our creatures are more useful to us for their utility than for beating down the horde of goblins or vampires or merfolk. So we need a few things to keep us alive till our engine is running. Crystalline Giant is a wildcard, as it gives us lots of useful creature counters that we can move around to other things as they need them. We don't care about the mill provided by Geralf's Mindcrusher but after he dies we can move the undying +1/+1 counter off him to buff up another one of our creatures and have a constantly regenerating creature with decent power and toughness to protect ourselves. Imprisoned in the Moon can remove a troublesome creature our opponent has for a bit (even their Commander) and Inevitable Betrayal Lets us steal any creature in an opponents library (you should probably pick their best one). Interesting interaction to note here: If you cast As Foretold with Inevitable Betrayal in hand, instead of suspending Inevitable Betrayal you can free cast it using As Foretold (as it's a sorcery with 0 cmc) getting you one of your opponents best creatures IMMEDIATELY. Inventive Iteration has some utility with our remove counters strategy, but also flips into a creature that will slow down our opponents casting. Myojin of Cryptic Dreams can give us an indestructible counter for another creature we care about more, or spend it to triple copy a spell we want a lot of. Sinister Concierge lets us politic a bit and remove the biggest threat from the board temporarily when it dies. Time of Ice can let us slowly tap down all our opponents creatures and perma-lock them tapped or when we are ready bounce them all back to our opponents hands.

Counter Manipulation

Ah, here are our main tools for removing (and in some cases adding) counters to our various pieces. Chisei, Heart of Oceans was actually the previous commander of this deck before Goldberry, River-Daughter and he still works as a decent blocker that can remove counters for us every turn. Just make sure you don't play him without having counters to remove on stuff or he'll sac himself. Displacer Kitten lets us remove all the counters from a piece to start it fresh by flickering the piece in question. Estrid's Invocation will let us copy a saga we are using for double the effect of the saga. Thrummingbird and Flux Channeler will let us proliferate counters, either good ones from Crystalline Giant we want to spread around, time counters on As Foretold to be able to free cast higher CMC spells, or just accelerate a saga toward a chapter we want. Jhoira's Timebug helps us remove time counters specifically from cards like Chronozoa and Inevitable Betrayal.

CC Synergy Win Con

These are the cards we are looking for to close out the game. Chronozoa is another one of my pet cards, but as the only mono-blue card with vanishing we want to remove counters from, It can get out of hand quickly if left unchecked. Dark Depths counters get us Marit Lage, who is a game ending creature in it's own right, and Thespian Stage can short cut that for us as well (I'll describe that interaction down below if you need it). Kiora Bests the Sea God is the best card in this deck as each chapter ability is something almost game ending if we continually repeat it. Want not 1 but 2 Marit Lages? want a copy of a creature you stole? Sakashima the Imposter can copy a utility piece we need or a game ending creature we have. Time Warp because sometimes one extra turn is all you need, and since it just goes to the graveyard The Mirari Conjecture can be used to use it again and again.

Removal/Counters/Wipes

Since your in Mono-Blue, it would be irresponsible not to make use of some counterspells, and the legendary Cyclonic Rift. Notably Decree of Silence can shut down your opponents ability to cast spells as long as you can keep it from 3 depletion counters accruing. The Phasing of Zhalfir 's Read Ahead ability lets you start it at whatever chapter you want, so you can use it at an immediate wipe that will just give your opponents 2/2s, or keep it as a ticking time bomb on the field, phasing out the piece you want to keep until your ready to let it explode.

Utility Lands

Demolition Field and Strip Mine are standard single target land removal for me, between the occasional Cabal Coffers, Gaia's Cradle, or Field of the Dead decks it is key to have a way to deal with problem lands your opponents are using. Minamo, School at Water's Edge is a blue mana or an untapping tool, and Nesting Grounds lets us manipulate counters. Reliquary Tower gives us no max hand size, which can be pertinent with some of our draw effects. The all star is Thespian's Stage, which not only lets us copy a really good land our opponents have in a pinch, but combos with Dark Depths from earlier. The way this combo works, is to have Dark Depths and Thespian Stage on the field. Usually to get Marit Lage, we need to remove all 10 of the ice counters from Dark Depths (Either through it's inherent ability that will ultimately cost us 30 MANA) or through our counter removal strategy. Instead, we can activate Thespian Stage to become a copy of Dark Depths. Because Dark Depths is Legendary, the Legendary rule applies and state based actions will force us to sacrifice one of our Dark Depths. We want to sacrifice the original, keeping the Thespian Stage copy. After State Based Actions are concluded, the Thespian Stage is now a copy of Dark Depths but notably doesn't have any ice counters on it. This will cause it to trigger the ability that sacs itself and makes our Marit Lage! Congrats, you just made a 20/20 Flying Indestructible creature for 2 mana.