Diving Deep with Sea Monsters: Nautilus Control Deck Guide

Hey there folks, I’m FaeGamerBoi and today I’m going to be breaking down the deck I’ve played and tuned the most since the launch of the Rising Tides expansion to Legends of Runeterra.

Hey there folks, I’m FaeGamerBoi and today I’m going to be breaking down the deck I’ve played and tuned the most since the launch of the Rising Tides expansion to Legends of Runeterra. I played 100 games with Sea Monsters, testing and tuning the list, and I believe I can give you well-informed opinions on how to build and run this deck. I’ll be going over the cards that fit this deck, and then going in-depth on the matchups, my personal experience and tier rating, then finally how I think the deck could evolve in a future meta.

Game Plan

This idea of this deck is quite simple and is based on two new mechanics of Rising Tides. First, Nautilus makes your Sea Monsters cheaper once your deck is down to 15 cards (referred to as Deep in game) and, second, Maokai mills your deck (referred to as Toss). Thus the idea was born to use Maokai as an engine to get you Deep and then drop Nautilus for incredibly cheap and powerful Sea Monsters to destroy your opponent!

In the beginning, my build was incredibly greedy, omitting many good stall and removal cards for the sake of getting Deep quicker, but that list obviously this did not last. The rise of aggro decks began while the meta was still in flux, and to succeed, Nautilus deck had to run some better anti-aggro tools. And so the list began to adapt and now we have the concept that I’ve settled on here.


This deck is a stall control list, but it differs from other control lists in that it doesn’t fight for the board as fiercely, because you can always take it back from your opponent once you start dropping Sea Monsters. You stall the board out with cheap creatures and spells to keep your Nexus healthy, and then once you hit turn 6 or 7, you begin to dominate with big creatures and the ability to play multiple Sea Monsters at a ridiculously low cost thanks to Nautilus. If you like to play big, splashy units and overpower your opponents, then the Sea Monster deck is perfect for you! So, all that being said, lets talk about the cards.

Core Cards

  • 3x Nautilus: Nautilus is a “build-around” card for this deck. He makes your Sea Monsters cheaper, he’s a force to be reckoned with, and his signature spell Riptide puts in a lot of work. Be careful not to run him face first into a Vengeance or a Will of Ionia and he’ll quickly overwhelm your opponent with hordes of huge units.
  • 3x Dreg Dredgers: Of all the Toss cards, Dredgers are the most irreplaceable. The rest you can mix and match, but a 1 mana 2/1 that Tosses and chump-blocks is always valuable regardless of the match up. It’s cheap, got decent stats and synergizes with the Deep theme.
  • 2-3x Jaull Hunters: Jaull Hunter is a premium 3-drop. Your opponent will sometimes remove it, but you still got a free Sea Monster out of it, and when it does manage to stick, it always finds value in destroying one of your opponent’s key units with it’s awesome 4 power and Challenger.
  • 2-3x Devourer of the Depths: You’re always going to run some amount of Sea Monsters, but which ones you pick depend on the most prevalent decks you’re facing. Devourer of the Depths is the most irreplaceable one, it’s good against all manner of decks and landing the Obliterate effect can be enough to completely lock the game for you. Just be aware that your opponent will try to remove or lower Devourer’s health to make its effect fizzle, play around this whenever you can. Special mentions go to using this effect on Grizzled Ranger or a unit with Unyielding Spirit applied to it.
  • 2x Jettison: This card seemed underwhelming at first, but that was before I started using it as a combat trick to trigger Deep during an opponent’s attack. If they don’t see it coming, this can be a devastating blow! Aim to hold your Jettisons and, by going Deep when your opponent is not expecting it, try to force them to waste removal or block badly. It’s worth noting that if you hit a Devourer with Deep when your opponent attempts to reduce its health you can get massive value, trading a Jettison for two of your opponents cards!
  • 1-2x Glimpse Beyond, 3x Salvage: Card draw is necessary in this deck to keep your options open and get you a little deeper into your deck. Glimpse is quite cheap, which can sometimes be useful in faster match-ups, and so I’m running it alongside Salvage. Mix and match these two depending on whether the cheap cost or the extra Toss is more valuable to you in the current meta.

Flex Cards

  • 2x Maokai:  A Toss synergy piece and stall tool, Maokai will often mill 2-4 cards and provide you with a Sapling or two to chump-block or challenge your opponent’s units. Maokai can be a bit weak against midrange decks (Demacia can have too much power on the board) and a bit of a liability in the endgame if you’ve already Tossed down too low – this is why I’m only running 2. Don’t try to mill your opponent out with him unless you absolutely have to, it’s not what this deck is aiming to do.
  • Anti-aggro cards (Hapless Aristocrat, Deadbloom Wanderer, Vile Feast, Withering Wail, Grasp of the Undying): You’ll want to run some amount of stabilizers or decks faster than you will tear you to shreds before you can even get close to your big endgame. You can choose which of these to run to your liking, but run more when aggro is super prevalent, and less when it isn’t. Deadbloom Wanderer scores extra points for being a Lifesteal unit as well as a Toss-synergy card, just watch out for Mystic Shots.
  • 2x Thorny Toad: I’m only running two copies of Thorny Toad as it can be really slow and a mediocre blocker (especially against Boomcrew Rookie and Crismson Disciple). It could really shine if Spiders start making waves again, but for now, the durable body and lifegain make it a fine 2-of.
  • 2x The Beast Below: Your midrange Sea Monster. Beast is the most boring unit in this flashy archetype, but it’s ability to come down on 4 will save you in many different spots, especially against Demacia. If your opponent doesn’t kill Beast before you get Deep, it will soon dominate the board. In a control-heavy meta, I can see cutting Beast for a different Sea Monster, but for the moment he’s incredibly valuable.
  • 2x Abyssal Eye: Abyssal Eye is a solid option for a control finisher. Having only 3 health is a big downside but the low mana cost makes it a lot easier to deploy than Terror of the Tides or Shipwreck Hoarder. If there were more Elusives in the meta, this card could be an easy 3-of, but for the moment it’ll do a fine job of chipping your opponent’s Nexus down a bit to set you up for Atrocity win. Drawing cards off it is gravy on top!
  • 2x Atrocity: This deck’s biggest weakness against control is having to play Nautilus into a Vengance or Will of Ionia. Attrocity turns this situation around, heavily punishing opponents who try to remove your win condition. Hold this card in hand for as long as possible to swing that 13 damage at them, and don’t be afraid to bank mana into turn 10 so you can play Nautilus with Atrocity in your hand as backup.

Tech Cards/Options

  • Thresh: Good option for the 5 drop slot in your curve, Thresh will often stall up midrange match-ups much better than Maokai. Unfortunately, his higher cost is something you’ll definitely feel in the aggro match-up and being able to summon Nautilus for free happens so rarely it’s not even worth mentioning. If midrange starts taking over the meta again, Thresh is a great replacement for Maokai, but until then, he’s just a bit too slow.
  • Dreadway Deckhand: I saw a few lists playing Deckhand at the two-drop slot instead of Thorny Toad and I honestly can’t deny the value. It sometimes blocks better and the Powder Keg will let your Vile Feasts, Grasps and Wails shine! The downside is the lack of lifegain that the Toad provides and the vulnerability of the barrel. Regardless, this is still a fine 2 drop and one I could easily see running.
  • Terror of the Tides: The strongest control finisher Sea Monster, but also the most pricey. Terror will push you past the line in a midrange/control match-up and allow you to get around almost any board state for the kill. I’m running Atrocity instead though because its value as a removal counter is much higher than Terror’s body and Fearsome ability. Also Terror’s mana-cost puts a huge hamper on it’s playability.
  • Lure of the Depths: This card can be very easily used in the control match-up and makes your Sea Monsters much easier to curve into. Unfortunately this card does almost nothing in the aggro match-up, and that being our worst match-up, I cut it. In a more control-based meta, this card will be the first to go back into the deck, as the value of putting Sea Monsters down a turn early should not be slept on!
  • Shipwreck Hoarder: Yet another anti-control finisher. In theory the Treasures sound great, but in my experience, they’re too random and not always very useful. Treasure Trove will occasionally hit something amazing, but I’ve had more games where it gives you cards that won’t do anything to help you win. Keelbreaker can clear the board, but it also puts most of your Sea Monsters into easy removal range, so it’s use is limited. And Platewyrm Egg can be useful, but often by the time you draw it, your board will be full, so it’s got very narrow applications. Terror is almost always going to be a more reliable finisher.

Match-ups and Meta

Over my 100 games, this deck boasted a win-rate of 55%. I further broke this down into: 63% against control (35 games), 60% against midrange (30 games) and 43% against aggro (35 games). Lets get into the details here and talk about specific match-ups.

Burn/Draven Burn/Discard Aggro

This match-up is rough, I’m not going to lie. Your deck has access to a vast array of anti-aggro tools, but overall the game plan of dropping a Nautilus will often give your opponent plenty of time to burn your Nexus down.

The cards you’ll want to mulligan for are: Hapless Aristocrat, Dreg Dredgers, Thorny Toad, Jaull Hunters, Deadbloom Wanderer, Vile Feast, Withering Wail and Grasp of the Undying.

Given a decent opening hand, your lines of play will be to deny your opponent as much damage as possible and try to wipe their creatures out so they aren’t able to attack around you. Hapless Aristocrat or Dreg on turn 1 will let you avoid the 2-3 opening damage. Vile Feast will kill quite a few aggressive units, heal you and give you a chump blocker, so it’s a very useful card in this match-up. And if you can drop Deadbloom Wanderer once your opponent has no mana to answer it with Mystic Shot, it can provide enormous value (healing you for 3, Tossing and trading for one of your opponent’s units).

Maokai can also be useful to provide chump-blockers and Challengers, but he can be a little slow to start, so don’t keep him in the opening hand. To win this game, you’re going to run your opponent out of cards in hand while keeping your own Nexus healthy, so use your resources as such. Be VERY careful about spending your mana on your more expensive units – I’ve won many a game simply by holding up mana for spells while my one Beast or Eye just chipped their Nexus down.

Corina Control

Your match-up with Corina Control is quite favorable. Their access to PZ removal won’t help them much against your Sea Monsters, and they’ll need to hold their Vengeance and Ruination for Nautilus, so you should have ample time to build up into your big plays and set up the win.

The cards you’ll want to mulligan for are: Glimpse Beyond, Salvage, Maokai and Atrocity. And don’t feel too bad for holding onto some Toss synergy cards, as they’ll definitely come in handy to get you Deep early and get your Sea Monsters out of range of PZ spells.

Your plan will be to draw as many cards as possible, Tossing where you can, to try and gain a lead on your opponent in terms of options. Don’t let Elise run rampant on the board early as it is very possible to get killed by spiders if you don’t have answers for them. If you’ve got Maokai, try and stick him on the board and get some activations of his ability – he’ll likely get Thermogenic Beamed at the earliest convenience for your opponent.

Once you get into range of Nautilus, you’re going to want to run him out once your opponent has used too much mana to be able to cast Vengeance so that you can have Atrocity available when they do, dealing a huge 13 damage to their Nexus. Other than that, your Abysall Eye’s should be able to threaten the opponent enough for them to use up their removal and your Devourer’s will occasionally be able to eat up a Ledros.


Assuming they don’t get a super fast start, you’ll actually be able to handle Bannerman and Scouts quite well with your end game (7/7 units block Demacia incredibly well). The key is to not let them dominate the board early and always try to play around Relentless Pursuit.

Mulligan for: Jaull Hunters, Dreg Dredgers, Beast Below and Vile Feast.

You’re going to want to keep your opponent’s board clear into turn 4, denying them a value Bannerman. Beast Below is a very solid blocker in the mid-game, and Jaull Hunters will get rid of Loyal Badgerbear super neatly. If your opponent tries to deploy Grizzled Ranger, eating it with a Devourer or casting Vile Feast on it is a pretty solid answer.

If you can, use Glimpse Beyond to deny Garen the strikes he needs to level up and force your opponent to play without extra Rally effects. If you can prevent the board being overwhelmed, Relentless Pursuit will become useless and as soon as you get deep and start dropping huge Sea Monsters, the game is over. Your opponent will occasionally use Unyielding Spirit to apply unkillable pressure, but if you can Devourer the unit or use Nautilus’ signature spell Riptide to shuffle them back into the deck, you will likely win you the game on the spot.

Karma Ezreal

This deck will give you plenty of chance to set up your Nautilus for the win, but be careful, they will sometimes be able to knock you out first if you give them enough targets to level Ezreal!

Mulligan for: Jettison, Glimpse Beyond and Salvage, also sometimes consider keeping one-of Nautilus or Abyssal Eye.

The name of the game is Tossing fast with minimal units, your Grasps will have a decent time keeping the board clear of Chump Whumps and Shadow Assassins, but you may need to commit some units to prevent yourself being killed by your opponent’s board. Make sure to weigh how quickly Ezreal can level up and try to deny this where possible.

Winning with Atrocity will be hard as Will of Ionia with Deny backup is a fairly common answer to Nautilus, instead try to beat your opponent down with Deep-buffed Abyssal Eyes. I’m sure it doesn’t need be said, but 3 health is in the prime range to get killed by many different PnZ spells, so hold back your Sea Monsters for as long as you can, then force out the Will of Ionias where possible. Karma is fairly easy to remove with either Devourer or Grasp, but make sure to play around extra answers your opponent may have. If you can kill one of both of your opponent’s combo pieces, they’re going to have a tough time winning!

Sea Monsters

The mirror match-up is an interesting one, both you and your opponent will have tremendous creatures blocking each other, so combat can be a difficult avenue to win through. The plan is to go Deep sooner and dominate quickly.

Mulligan for: Maokai, Jettison, Salvage, Jaull Hunters (if they’re running Maokai), Abyssal Eye and any of your toss cards.

Generally you will be playing whatever cards you can to Toss through your deck quicker than your opponent, and let’s not understate just how important Maokai can be in this goal. Maokai is above Grasp of the Undying and so is hard to remove, his ability will not only mill you, but also create units to fight your opponent’s board with and establish an early lead. If you can run a Jaull Hunters into your opponent’s Maokai, this will set them back tremendously! But try to play around Vile Feast when doing this.

Reactively respond to their cards as much as you can, rather than letting them respond to you, and you’ll get an edge: If they play Dreg Dredgers, play Thorny Toad, if they play Maokai, play Jaull Hunters, if they play Jaull Hunters, play Vile Feast, if they play Nautilus, try for Riptide. Don’t be proactive unless you’ve got no other choice, because almost every card in this deck will answer another one! Once you get Deep, Abyssal Eye will let you strike the Nexus in clogged boardstates and Nautilus is impossible to remove (unless they have their own Naut and use Riptide) so play him ASAP.


I think this deck has very solid legs to stand on in any meta because of the sheer number of tech cards available to it. With Riptide and Devourer of the Deep filling a niche for unconditional removal; all of the Shadow Isles anti-aggro and control cards; the midrange capabilities of Sea Monsters; and Jaull Hunters/Lure of the Depths being incredible support cards for the archetype, I think Sea Monsters will be a playable deck for a good long time.

The aggro match-up leaves something to be desired, but given the tendency for metas to shift toward control lists once the new cards have settled and aggro lists can be better played around, I can imagine this match-up being less relevant in future. Overall I’d say this deck is a solid Tier 2, my win percentage with it being at 55% percent means you can definitely climb with it.

Over time I expect it’s winrate to rise, because once aggressive lists become less prevalent, more slots are going to be freed up for synergy cards. Given the deck already boasts a >60% win rate against both Midrange and Control lists, I predict it’ll climb to the top of Tier 2/bottom of Tier 1 in the next few weeks. The main drawback to this strategy making it to the top of Tier 1 is it’s reliance on Nautilus and combat as a means to win, which are much more interruptable than for example Ezreal and Karma. But if you love the flavor/playstyle of the Deep, invest in Nautilus freely, he’s a super-safe bet and this deck isn’t going anywhere any time soon.

Thank you for your reading and I hope my insight helps you build an amazing Sea Monsters deck! If you’d like to chat with me about it and get my opinion on different cards, feel free to contact me on Facebook and Twitter and if you’d like to see me play it, I regularly stream on Twitch. You can also check out my content and guides on YouTube. Enjoy the rest of your day and I’ll hopefully see some of you soon.


Part Fae, all gamer. MTG player of two years, but currently his heart is with Runeterra. Card game theorist, lover of statistics and spreadsheets.

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