Rek'Sai - New Imperial Decree Tech

Rek'Sai Void Burrower

General play style:

When playing Rek'Sai your aim is to try and double conquer the battlefields each turn, and utilizing the Rek'Sai legend ability to search for answers. These answers tend to be; Cull the Weak, Undertitan, Imperial Decree, Salvage or more units this all depends on the match up. I've designed the deck to have two modes one where Undertitan is used to buff units mights for big swings and the other being Imperial Decree where using small units to one shot multiple big units.

Starting Hand:

After deciding who is going first or second we need to sort out our hand, with eleven 2 drops and five 3 drops in the deck this almost guarantees a turn 1 play. If you don't get a 2 or 3 drop, then mulligan 2 cards. When mulligan cards Undertitan is not a good card in the starting hand so mull it and spells like Cleave or Blood Rush can also be mulligan. The best 2 drop is either Carrion Dredger or Soaring Scout, especially for going first I tend to go with Dredger over Scout due to the Bird that spawns when Dredger dies. Both are good early game as Soaring Scout allows for a quicker ramp while Carrion Dredger allows you score more points constantly while building units in base. Faithful Manufacturer is best 3 drop for going second because allows you to do a double conquer and begin scoring lots of points very quickly. Finally I tend to mulligan Undertitan even if I have turn 1 play to try and get better early game or mid game cards.

Early Game:

We want to get on a battlefield as quick as possible due to the nature of this deck, being able to play a lot of small units our early turns makes for a very aggro play-style. So in turn 2 because of the amount of Units that have the Deathknell ability we can conquer a battlefield, then using Cull the Weak we kill our own unit to slow our opponent down or play Escaped Grayback killing own unit to empower it activating the Deathknell. This in both cases removes our unit off the battlefield and providing us this more units or resources while allowing us to double counquer next turn. Finally during the early game we don't want to have units sitting on battlefields collecting hold point by putting more units on there as we are aiming to use our Legend ability as much as possible during the game.

Rek'Sai Legend Ability:

The Legend Ability allows you to reveal the top 2 cards of your deck and you may play one of them and recycling any play cards not played. This ability is great for finding cards and synergises great with both Undertitan and Rek'Sai Breacher. When Undertitan is revealed you get 2 floating runes this great to be able to play more units onto the field and Rek'Sai Breacher is also great because units not played from the hand can be accelerated. As such you use the top of your deck like second hand which means you can all ways play cards provided you can conquer a battlefield but it does comes with the downside of your opponent getting more information about your deck.

The part that make Rek'Sai difficult to play is the recycling of cards off the Legend ability, as the "Gambling" legend we want to mitigate recycling of good cards. So when using the legend ability we always want to have some runes open to do that, also keeping track of how many times we have seen cards like Cull the Weak and Undertitan allows us to card count in a way. So pen and paper is a great tool to note down both our own cards and our opponent's. While also deciding if we want to activate our legend ability, because if we are very far ahead then is no point to activate it and risk wasting a Cull the Weak or an Undertitan. Also the signature spell Void Rush is better version of the Legend ability and as such is a great way to search the deck and play a card a reduced cost while also adding the other to hand.  Finally because the list is running Noxus Hopeful playing a card before activating the Legend ability will allow you play it for cheap and free if seen of Void Rush (it's a mistake that i have made far too often).

Mid Game:

So in turn 3 we start to amass units in base while using the lest amount of might possible to conquer battlefields and use the Legend Ability to dig through the deck. While building up units making sure not to over commit units in your base, because if your opponent has Ruination, Downwell, Angler Beast or any other board wipe ability this can totally ends your game. In the case of Downwell or Angler Beast it not the end of the world but you need to start rebuilding quickly. So always keep a unit or two in hand like a Red Pyke which you have play recycle a rune to ready him and get +2 might which can help recover the game. During the mid game we want favorable trades to by using Blood Rush, Cleave and Inferna to pump might to get good trades. You can also hide Red Pyke to either use during a showndown to get your opponent to use more resources to win combat or at the end of their turn to have ready on your turn to then use it's ganking ability to gank across to other battlefield.

Modes:

The Undertitan mode is designed for most matchups to make your opponent is going to struggle to keep up with your pace, this is due to the amount of units you can fielded by using Undertitan's ability you are getting more Energy. So when the end game arrives your should have a lot of units in base allowing you to play the Undertitan to Buff all other units by 2 might. This is the move to crush your opponent and close out the game ideally if you have a few Rune open you can then use Cleave or Blood Rush to pump units when need in the showdowns (So ideally hold on to 1 or 2 of these spells). Also Rek'Sai Breacher is a great unit to have in the End game as it allows you to accelerate unit spawned off Noxian Emissary and Carrion Dredger this may allow you to get those conquers if you need a few units to close out the game.

"There is an argument to be made that one Imperial Decree could be ran in main deck as it would provide some flexibility in variety of matchups as such test it out against a variety of matchups for game 1 in particular"

The Imperial Decree mode is designed for big unit matchups like Jayce Aurora (Elder Dragon), Akali (Big Bird) and LeBlanc (Rift Herald and Thousand Tail Watcher). This mode takes advantage of a lot of small units to be able to kill this big units and the in the case of Elder Dragon the unit was already going to die ID takes it down with it. This mode is to provide more utility to handle this threats after the stack deck ban and the surge in popularity of these decks. Being able to kill annoying threats like Astral Heron is great on top of the fact that no unit is safe in their base with Falling Star and Decree of Rage which the latter can't be countered. Because green decks are running Astral Heron, Vilemaw and Zhonya's Hourglass you going to have to kill big unit's multiple times Imperial Decree allows for that. Vilemaw is a very annoying unit for this deck to deal with as such killing it this way gets around the ability of "units with less than it might don't deal combat damage".

"There is a part of me that thinks this mode could be good against Azir but due to the amount of gear hate that I am bringing and that it is using ID which allows it to breaks through the large might battlefields and ignores any negates but requires me to have more units that Azir which is going to be tough to do because the Arise allows them to rebuild in a turn."

Battlefields:

Trifarian War Camp - This is your going blind Battlefield it fairly good one for you in most matchups because with amount of units you are able to play, most deck in the meta can't keep up except for Azir.
Forbidding Waste - This is your going second Battlefield it great when your opponent conquers here and as they suffers a -2 might when one unit defends alone. On top of the fact that for you don't mind the -2 because we using primarily 1 - 2  might units and dying often helps us but also if we need to hold we can get around this de-buff easily with the amount of units we have.
The Candlelit Sanctum - This the going first battlefield and the most complex battlefield, because when you conquer the battlefield you can trigger Legend ability, you going need to decide if you are doing activate one or both of conquer effects. You are always going to trigger the Sanctum but as I have said before some time you are not going activate Rek'Sai legend ability. The important thing is you need to announce to your opponent if you are triggering one or both abilities. The important thing and why we use The candlelit Sanctum first and then Rek'Sai ability is because it allows us to recycle bad card for the matchup like a Salvage in game where there is no gear allowing us to try and find better cards. If we are only using the Sanctum effect then we re-order or recycle cards to draw a better card (I.e rigging the deck).

Sideboarding:

Brittle Steel - This is gear hate and such is needed for Aurora decks and Azir mainly. It is slightly better Salvage due to it having flow and I to tends to swap it in removing Cleave.
Decree of Rage - Used as an unstoppable damage dealer for green decks by passing Defy and Not So Fast. Used to replace Cleave.
Decree of Unity - Used to remove troublesome purple units like Rhasa or gear like Last Rites depending on the state of the game and is very flexible because of that. We replace Cleave for this.
Ferrous Forerunner - It's annoying unit to kill and is great into Aurora because it spawns more units. We replace Undertitan.
Forge of the Future - Used to disrupt Kennen decks and slow them down. 
Hidden Blade - Used in Aurora matchups to kill our units to draw when Elder Dragon shows up, we react to it targeting units for damage. We replace Cleave with it.
Imperial Decree - Read the modes section again on why. We swap Undertitan out.

"There is an argument to be made about using piercing light in this list replacing something else probably Ferrous Forerunner if anything."

Runes:

It a simple section but I use 7 - 5 split because of the heavy use of Red Runes because of Falling Star. I haven't found this split to be to bad as when I need a Yellow rune I always have it. We mostly use Red Runes when playing Void Rush because we have more of them and Yellow Runes are for mainly used for Cull the Weak.

Final thoughts:

Rek'Sai is a very fun deck to play and it's pretty easy to learn but hard to master. I made quite a few changes from the older list I was using. I dropped Daring Poro for Soaring Scout to get a bit more speed and allow for more aggressive plays by recycling runes. I moved a Salvage in main due to the amount of gear deck being played, increased the amount of IDs to help deal with big might units and brought in more gear hate with Brittle steel. 

This is my first Guide I wrote and I wanted to include as much detail on card choices and usage, unfortunately there are so many ways a game can play out that I can't write what I would do in every situation. So I hope some generalisation is fine, also I wanted to focus in on specific matchups like Jayce, Akali, Azir and LeBlanc decks as they are currently popular in the meta. There choices I made as I like flexibility of a card, for instance Legion Rearguard is a great 2 drop but I prefer Red Pyke because in the situation of acceleration Pyke comes out with more might at the same cost 3 energy and 1 rune but also it has hidden and ganking as such that provides more ways to use him. So have fun playing the Gambling Legend.