Merfolk

Merfolk of the Pearl Trident card art

Last time was Zombies; today I look at mono-blue Merfolk.

Merfolk are slippery, and so it is no surprise that their strength in Magic is being unblockable. Some creatures, as we shall see, have this ability natively. Others get it through combos (granting islandwalk and turning opponents' lands into islands) or other means. Whatever the case, most merfolk decks I have seen leverage this mechanic.

Arena options for Merfolk are quite limited. Most options came out of the Ixalan/Rivals of Ixalan block, which featured blue and green merfolk. Keeping it to mono-blue, here are two options:

Merfolk (1)

3 Tempest Caller (XLN) 86

2 Seafloor Oracle (RIX) 51

1 Riverwise Augur (RIX) 48

2 Watertrap Weaver (XLN) 87

4 Merrow Reejerey (LRW) 74

2 Library Larcenist (M21) 55

1 Kopala, Warden of Waves (XLN) 61

4 Deeproot Waters (XLN) 51

2 Thassa's Oracle (THB) 73

3 Silvergill Adept (RIX) 53

4 River Sneak (XLN) 70

4 Mist-Cloaked Herald (RIX) 43

3 Merfolk Trickster (DAR) 56

4 Opt (M21) 59

21 Island (SLD) 102

River Sneak and Mist-Cloaked Herald are natively unblockable. Plus them up with Merrow Reejery and generate an army with Deeproot Waters.

Merfolk (2)

3 Tempest Caller (XLN) 86

2 Seafloor Oracle (RIX) 51

2 Riverwise Augur (RIX) 48

3 Watertrap Weaver (XLN) 87

4 Merrow Reejerey (LRW) 74

4 Deeproot Waters (XLN) 51

4 Silvergill Adept (RIX) 53

4 River Sneak (XLN) 70

4 Mist-Cloaked Herald (RIX) 43

4 Merfolk Trickster (DAR) 56

4 Opt (M21) 59

1 Svyelun of Sea and Sky (MH2) 69

21 Island (SLD) 102

This second iteration isn't much different. Same general concept. To let your other (non-unblockable) Merfolk through, use cards like Tempest Caller, Watertrap Weaver, and Merfolk Trickster. Seafloor Oracle can provide some nice card draw, especially when multiple creatures get through.

Other Cards/Ideas

Merfolk decklists  outside of Arena don't vary much for mono-blue, either. These two decklists highlight just how similar such builds tend to be:

- TappedOut

- MTGGoldfish

Merfolk lords (Lord of Atlantis, Master of the Pearl Trident, Merfolk Sovereign) pump your creatures and make them unblockable (if you can turn your opponents' lands into islands).

Speaking of island creation . . . Reef Shaman, Spreading Seas, Aquitect's Will, and Streambed Aquitects are helpful options.

Various creatures help you get merfolk out of your deck and onto the battlefield more quickly, either through card draw, limited deck search, or other abilities:

Several merfolk creatures help with card draw:

And some help protect your aquatic army:

Finally, instants like Spell Pierce, Vapor Snag, and Deprive are common choices to protect your team or mess with your opponents':

Ultimately, it's not hard to make a decent merfolk deck using some combination of the above cards. It is a fun tribe to play.