At its core this is a G/U Devotion deck. However, the red splash allows you to play Domri Rade, one of the best Planeswalkers in Standard, In addition to great sideboard options such as Xenagos and Mizzium Mortars.

Prophet of Kruphix allows you to "como off" and can lead to very broken situations. This + Garruk = Success. The other non-land comboish card is BTE. BTE is very key in your devotion strategy, as it is a "free" 2 green devotion. Your key land is Nykthos, Shrine to Nyx. Nykthos allows you to gain unreasonable amounts of mana, especially paired with a Voyaging Satyr or if there is another copy in your hand.

Your mana dorks are Elvish Mystic, Sylvan Caryatid, and Voyaging Satyr. Elvish Mystic is arguably the most important of the three as it allows you to ramp very early in the game (eg. T2 Domri). Sylvan Caryatid is very important vs removal heavy decks, as you mana dorks are critical to success (Also it dodges Drown in Sorrow). However, Caryatid is a liability against control, as it fails to put on any pressure. The 3rd mana dork is voyaging satry. Satyr is one of your combo pieces with Nykthos, as it allows you to activate Nykthos more than once. When you do not draw Nykthos, however, it is often just a worse Caryatid. Cyclonic Rift is your only interactive spell in the Mainboard (besides Monstrosity). It can both overload into game-ending situations or just be a nice tempo swing against many decks.

Your Planeswalkers consist of Kiora, Garruk, and Domri. Domri is a nice early card-drawing machine, and can take out bothersome creatures. However, drawing multiples in this deck is generally not your friend (hence the 3 copies). Garruk is Super-Domri. It draws multiple creatures per turn, and 1 activation can sometimes be lethal. Kiora is VERY important for your strategy. Her -1 is nice, but her +1 is where she really shines. In games where you do not just combo off, you may be forced into a slower game. When this happens it is important that you are able to lock down opposing threats (such as Desecration Demon in Mono Black).

Your BFC's (Big Fat Creatures) consist of Arbor Colossus, Polukranos, Prime Speaker Zegana, and Xenagod. Polukranos is very important against aggressive decks as it gives you an early roadblock (usually coming down on Turn 3). Against enemy creature-based decks, it works as a pseudo-removal spell, capable of taking out most bothersome creatures. When paired with Nykthos, Polukranos works as a one-sided removal spell. Arbor Colossus is not only important because it is a big, dumb, creature, but also because it fights opposing Specters and Desecration Demons very well. If you have run Mono Black out of relevant removal spells, Arbor Colossus can take over a board very quickly, using its Monstrous ability to dispatch scary Desecration Demons. Prime Speaker acts as your 5th Garruk, except this thing hits peoples faces, hard. Also, Prime Speaker is not as reliant on large creatures as you may think. Even when your largest creature is a Burning-Tree Emissary, the 3 cards that you gain off of Zegana can be very important in refueling. The last scary guy is Xenagos, God Edition. This creature can easily finish off opponents, or at the very least force them to block heavily. As this deck is a Devotion based deck, it is not very hard to gain the 7 devotion needed, and a big indestructible dude is generally pretty good.

The sideboard is very heavily focused on Control decks. The 2 Xenagos, the 4 Mistcutter Hydra's, and the 2 Unravel the Aether are all potent tool against UW variants. However, these tools all have uses outside of the control matchup. Xenagos is also very good against Mono Black Variants, applying a good amount of pressure while having the ability to negate their Demon. Note that it does struggle against Lifebane Zombie, as an activation of the 0 ability will leave it unprotected. Mistcutter Hydra is a very impressive creature in the Mono Blue matchup, and can be game-ending if you manage to accumulate a large amount of mana. Unravel the Aether, while mostly for Detention Spheres, is also very good if you run into the Naya Hexproof deck or the UW Devotion deck, which are both packed with a good amount of enchantments. The next sideboard slot belongs to Mizzium Mortars. Mortars is a very important removal spell against any opposing creature deck. Also, with an abundance of mana dorks, the Overload is not unreasonable. One matchup where having Mortars is very good is against and Pack Rat deck. If your opponent lands a turn 2 Pack Rat, you will want mortars to either kill it on the spot, or overload it on turn 4 or 5. The four Nylea's Disciples should be fairly self-explanatory. You want this card in any aggressive matchup, as Devotion for 7+ is not unreasonable. Drawing multiples is often game-ending.

This concludes my description for RUG Devotion. If you made it all the way through this, good for you. Any advice on the list would be greatly appreciated. Thank You!!!