Now running 24 lands (from 23) with 2x Zhalfirin Void - nice synergy with Kefnet and gets us access to some scry lands.

Also 2x Vraska Contempt (was 3x)

Instants/Sorceries (28)

Draw/Filtering

4 Opt - Important for smoothing out opening draws and finding land early, a good copy target for Kefnet, and makes copying spells on your opponents turn possible. We play 6 counters in this deck. If you Opt with Kefnet on board (on opp turn) and have 2 mana open, you have a ~1/5 chance to Opt into a UU Sinister Sabotage or a U Negate with the opponent spell on the stack.

1 Discovery // Dispersal - Nice 1 of. Good copy target, but only went with one copy because Opt is castable on opponents turn and Dispersal is too expensive for us when not copied for 2 less mana. Helps order draws for Kefnet

2 Drawn from Dreams - Incredible copy target - very good for finding more threats to juice your hand with. I think 2 is the right number, heavily considered three but felt too clunky.

Counters

2 Negate - Quality turn 2 counter, important for countering 3feri and reanimator spells. Helps protect our threats etc

4 Sinister Sabotage - We need at least six counterspells IMO, and Sabotage gets the spot because of the surveil which helps Kefnet's copying. Helps find 4th land

Removal Suite

3 Cast Down - Quality cheap removal. Experimented with Moment of Craving and Disfigure but Cast Down felt superior in this meta - hitting Krasis, and Cavalier of Thorns etc. I had 4x at one point, but trimmed it to 3x after the addition of Finale of Eternity.

1 Finale of Eternity - Important 1 of that I did not consider initially. This is a versatile card, and adds a flavor of removal that Ritual of Soot, Cry of the Carnarium, Cast Down, and Vraska's Contempt don't have: being able to remove big creatures in multiples. Good copy target

2 Cry of the Carnarium - Had 4x at one point, dropped down to 2x which feels right. Considered putting extra copies in the sideboard but didn't. Great copy target, one of the main reasons I kept the black and blue mana sources equal was to ensure a good shot at double black mana on turn three.

2 Ritual of Soot - Destroyer of Feather, Orzhoz Vamps, Elementals and dorks etc. Great card and copy target, misses all of our threats.

3 Vraska's Contempt - Started with 2x, went to 3x. This is the right number IMO. Great copy target, flexible card, nice lifegain etc.

Hand Disruption

4 Thought Erasure - One of the best Dimir cards overall, essential inclusion to either clear the way for our threats or weaken their hand and/or gain intelligence. The surveil is strong with Kefnet as well, and this is a nice demoralizing copy target. If you have an Opt in hand, and you know Thought Erasure is on top of library... and you have Kef on board, you can thought erasure on their draw step (happens sometimes :). Helps find third land

Creatures (8)

3 God-Eternal Kefnet - The boy himself. Recurring threat, centerpiece of the deck. Weak to bounce and steal. I strongly believe that 3 is the perfect number of these to run. 2 is too few

2 Nightveil Predator - Very important 2x. Can't be bounced by Teferi, blanks most removal, very good vs Feather, Mono R, Cavalcade, Grixis, Vamps, etc. Dropping this after your opponent wraths Kefnet and Gales back into your deck usually brings a concede.

3 Cavalier of Gales - Brainstorm ability is juicy with Kefnet. But there is some depth to the decision making:

If you think your hand is about to be disrupted, hide your best spells on top of your deck.
If you think Cavalier won't live till your next untap, put your junkbin cards on top and let opp shuffle your library for you before you scry 2.
If you think Cavalier will live till next untap and you have Kefnet on board, order some juicy copy targets on top of library.
Enchantments/Land

1 Search for Azcanta // Azcanta, the Sunken Ruin - 1 of for the scry to help Kefnet copying. Flipping is situational. If you don't have a threat in your hand, you can't find one with flipped azcanta - so be aware. I experimented with 2x copies, but 1x felt right. 2 was a little slow and I didn't like the possibility of opening hand with 2x.

1 Memorial to Genius - Very nice 1 of. 2 is too many, 0 is too little. Love to see this in my opening hand for T1 land or later in game. Yesterday I sacced Memorial on Opp's turn while he was swinging with lethal (vamps) and I drew a Ritual of Soot off the top and wiped his board instant speed for BB into concede.

Notable Exclusions

Enter the God-Eternals - Too slow in my opinion. Additionally, this deck does not benefit from putting 4 cards into graveyard... and too many decks benefit from graveyard stuffing. Would be a nice copy target, but is bad IMO when not drawn with Kefnet already on board and the token has almost no value vs 3Feri.

Mission Briefing - Could be a good 1 of, but wanted to keep this deck lean.

Doom Whisperer - Dies and does not return from Cast Down zzz

Walk the Plank - I think this card is very relevant in this meta, but no instant speed keeps Cast Down in my deck (EOT Cast Down is vital vs Simic Flash)

Eldest Reborn - Most boards are going too wide to get value from this

Sphinx of Foresight - This was a 1 of that I had mainboard for a while. It was fantastic when in opening hand, but never lived longer than a turn on board. Would be great synergy with Kefnet if he was more durable like being Legendary or something

Narset's Reversal - Only a good copy target on opp turn when Opt'ing. Somehow did not see a lot of Nexus lately, so no real pragmatic need at the moment.

Augur of Bolas - Would generate value. Could be an anti aggro sideboard option, but misses our creatures... and we are generally searching for them.

Blast Zone - Make this the 24th land? I don't like the colorless... our deck wants to get to 2B 3U as soon as possible and then see no land other than Memorial to Genius for rest of the game.

Blink of an Eye - I like that it has the potential to draw a card on opp turn, and is a very nice copy target, but it didn't make the cut in the end - mainly because I don't like it vs Simic Flash or Mono R

Moment of Craving - Amazing against Adanto Vanguard

Sideboard - Pretty standard Dimir SB. Would appreciate thoughts on what to include that is not there currently. I'll probably remove the Lily and the Ugin to be honest.

Tips for playing: You really want to see a creature in your opening hand - 65.4% chance of having one or more creatures in opening 7