FlashWhen Swift Warden enters, target Merfolk you control gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)
Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)As long as you have the city's blessing, Slippery Scoundrel has hexproof and can't be blocked.
When Forerunner of the Heralds enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.Whenever another Merfolk you control enters, put a +1/+1 counter on Forerunner of the Heralds.
When Form of the Dinosaur enters, your life total becomes 15.At the beginning of your upkeep, Form of the Dinosaur deals 15 damage to target creature an opponent controls and that creature deals damage equal to its power to you.
Enchant creatureEnchanted creature gets +2/+1 and has first strike.At the beginning of your end step, if you didn't attack with a creature this turn, sacrifice See Red.
Menace, Discard a card: Tomb Robber explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)
Equipped creature gets +2/+0, has menace, and is a Pirate in addition to its other creature types.Whenever Captain's Hook becomes unattached from a permanent, destroy that permanent.Equip
Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)Skymarcher Aspirant has flying as long as you have the city's blessing.
When Jungleborn Pioneer enters, create a 1/1 blue Merfolk creature token with hexproof. (It can't be the target of spells or abilities your opponents control.)
When Induced Amnesia enters, target player exiles all cards from their hand face down, then draws that many cards.When Induced Amnesia is put into a graveyard from the battlefield, return the exiled cards to their owner's hand.
When Bishop of Binding enters, exile target creature an opponent controls until Bishop of Binding leaves the battlefield.Whenever Bishop of Binding attacks, target Vampire gets +X/+X until end of turn, where X is the power of the exiled card.