this already has 3 three drops
4 drops in black/blue are usually below the curve
the emissary is not

Naiad. Not all emissaries are killers. The black one is kind of weak. He's not unplayable, but I don't jump on it like I do on the others.

Emissary is death incarnate. It forces misplays like a master and is good either on its own or bestowed to something else while turning every useless topdeck-mode Disciple of Phenax into a potential combat trick

more Blood-Toll Harpy may come around if black is blocked

Whew, emissary vs. naiad is very tough. Even horizon scholar is pretty tasty. I think Emissary. Really the only blue we have is ashiok anyway, and ashiok kinda combos (because you can toss your own creatures for +2 and play theirs instead)

You'll make shipwreck singer cry.

shipwreck singer is no slouch

sorry siren you are a real blue card, too!

I'd go for Naiad.

I say Naiad, Emissary is exciting but not as good of a bestower. Evasion is very powerful. Our Gray Merchant is already really good with two disciples in the deck so devotion shouldn't be a major concern.

future pick notes: we need actual removal, especially if we're going all-in on ashiok. Our blue also needs to be better so it isn't just a two card splash (gainsay is not a maindeck card I am sorry kids)

I see no problem with a 2 or 3 cards splash in an otherwise mono black deck. I drafted a black devotion deck last week with 2 griptides as the only blue cards (and 2 returned phalanx) and it worked amazingly.

on the other hand, good blue creatures are rare

and if this deck is going to attempt a dissolve it will want a blue back bone of islands and some other blue spells

one could voyage's end the ashen but if that's a plan
than one would want other creatures with on entrance effects

Being heavy black makes both merchant and pharika's cure better, and making good cards work better sounds like a good idea.

Emissary

Dissolve is not really an important blue spell in this format.

Voyage's end is an amazing card in this format and requires absolutely no EtB effects on your own creatures. You almost never use it on your own stuff. Usually you use it to make auras fall off or to mess up monstrous and heroic. Or just as a tempo play, that's fine too.

Naiad. Wind drake is usually good in draft.

This is a tough pick. I think I'm going naiad here.

Naiad just seems like a better card overall, but I'll admit to having not seen nor played the emissary at all.

Pack 1:

Wingsteed Rider
Magma Jet
Baleful Eidolon
Gray Merchant of Asphodel
Shipwreck Singer
Disciple of Phenax
Felhide Minotaur
Pharika's Cure
Disciple of Phenax
Gainsay
Lagonna-Band Elder
Opaline Unicorn
Unknown Shores
Yoked Ox

Pack 2:

Ashiok, Nightmare Weaver FOIL
Nimbus Naiad

Next...

Phalanx Leader
Tormented Hero
Sentry of the Underworld
Nessian Courser
Thassa's Bounty
Defend the Hearth
Leonin Snarecaster
Akroan Crusader
Crackling Triton
Opaline Unicorn
Lightning Strike
Lash of the Whip FOIL

Lash of the whip.

I'm really surprised to see the Phalanx Leader.

Phalanx Leader, maybe we splash some white.

~SE++