+1 for Sea Monsters! :)

I feel like Tromokratis might be a better general for this deck. Thassa comes down early and gives you tons of value from scry, though, so she's a super solid choice.

@ALX: Thanks!

@Steaditup: Tromokratis was my first choice as commander, but as mentioned Thassa is better value throughout the game. I forgot about Tromokratis when I wrote the description. I have since corrected my error :)

I dig the deck. +1

I like it! I'm working on building a similar deck with Endless Oceans, if you want to take a look.

i like the deck. i have a similar edh deck (not posted on this site) that i'm playing with that is less sea monster than it will be by the time i'm done, but i've been looking for cards for it. if you want to really grab the mana out of your deck and start throwing down beasties, add green for all the awesome ramp spells, even if you don't use many green spells other than ramp and a few creatures. Kruphix, God of Horizons is a house with his ablilty to store mana and to eliminate hand size limit. last time i played i had 10+ cards in hand for more than a few turns. (especially and leaving your U/G land untapped with 10 cards in hand makes people nervous. green also gives you spells like Time of Need to help you fish for creatures.. if you wanna stick with blue, which i totally understand cause blue is the best color, some flavorful creatures for the deck could be Void Stalker , Roil Elemental (works well with Soramaro, First to Dream she could also be another ALT general if you stay blue), and Vortex Elemental as well. they'll help with your bouncing/control. and maybe Expedition Map over Kraken's Eye . the eye is nice flavor, but useless basically, where as the map can help you grab your nice lands. good luck with your build! always happy to see a sea deck!

This feels like a commander deck should feel. Everything is on theme, but the deck is still coordinated and efficient enough to actually win a game. People tend to either go way too hardcore with their decks trying to win at all costs, or they go too overboard with the theme and never win a game.

+1!

Take a seat junior Underwater Friends

Expedition Map ramps and fits your treasure finding theme. Finds utility lands too

Brainstorm + any shuffle effect is amazing (or scry i guess?)

Soaring Seacliff and Faerie Conclave are both very useful.

Run Rhystic Study just do it. dont even question it, its good.

Jace, Architect of Thought can either get you some decent draws or can stall an opponent. Its super cheap now that it's in a duel deck.

@maxon: When researching the deck, I was looking at a kraken theme, and thought about Wrexial, the Risen Deep , then leviatans like Simic Sky Swallower , but I just couldn't find enough interesting cards in those colors for my sea creature theme. I'm contemplating Roil Elemental because I like that card a lot, and I'm going to put Expedition Map in soon.

@TempestMK4: Thanks! I really want as many cards on theme as possible, but I just can't get myself to run straight-up bad cards. Honestly, I'm not much of a fan of the merfolk, but almost all of them are useful. I'm currently building out the sideboard with possible swaps for them, but the current deck is what I'll be running for a little while.

@MarkerD: Nice deck, much more on theme. I've already snagged a few cards to put in my sideboard :)

@Grimgrinner: I originally had Brainstorm and Jace, Architect of Thought in the deck, but took them out in favor of alternate draw spells. I would love to put in a bunch of blue goodstuff, but I want to stay as close to the theme as possible.

Love it! i also have a mono blue thassa EDH deck The Drowned God. I think any mono colored deck should have Caged Sun , and Hall of Triumph . I also found Blustersquall to work very well.

Caged Sun is really good, but it depends on how aggressive I want to make this deck. I've put that and Hall of Triumph in the maybeboard for now.

Man, that maybeboard just keeps getting bigger. Guess I'll need to make some decisions soon :)

Thanks Valentine35!

I'm surprised you're not running Coastal Piracy . Check out my similar deck if you want some ideas! Zegana, Commander of the Sea

Also, Flow of Ideas could net you some really good card draw mid-late game. It also fits your theme.

Flow of Ideas sounds pretty good and very much on theme. I'm not sure on the Coastal Piracy because I have that effect with Bident of Thassa and it's not completely on theme, but it never hurts to have more draw effects. Thanks CastleSiege!

It's never bad to have more than one of the same effect, especially when it nets you card draw. I don't think coastal piracy is too far off your theme either since I'm sure pirate ships could be attacked by sea monsters! :p

PrestonShilling

[Serpant of the Endless Sea] seems like it would make a good addition

Serpent of the Endless Sea

Thanks deathtaker26, but I don't like creatures with restrictions on them. Though, maybe I should be going more islandwalk and turning lands into islands. What does everyone think?

I could also use some suggestions on replacements for cards in the maybeboard. Thanks everyone!

More food for thought - Are merfolk true to the sea creature theme? I feel like no, but I like the effects they bring. Anyone have an opinion there? Keep in mind I want this deck to stay casual but formidable.

I like this...EDH needs more theme decks that are still strong.

What do you think of Quicksilver Fountain ?

Thanks MindAblaze!. I like Quicksilver Fountain and already have it in the maybeboard, and I'm leaning more toward it being in. If that's the case, I may rethink Serpent of the Endless Sea .

Ahh...Yes, I missed that. It becomes much better when you have Islandwalkers out to take advantage of it. I've even seen it used for control purposes with the person bouncing it before all the lands on the board are islands.

FeralKitten, you've seen mine already, so you probably know that I'd vote in favor of counting Merfolk toward the sea creature theme. I've got several in mine that do great support, like Tideshaper Mystic , which helps Islandwalkers and creatures like Serpent of the Endless Sea . Deepchannel Mentor isn't bad either as a mid/late game way to do a good chunk of combat damage they can't block.