I was not that blown away with Kaya, Ghost Assassin when she was spoiled. I thought she was very interesting, but felt that her lack of ability to permanently affect the board would be problematic. This coupled with lots of strong alternate options for planeswalkers and  four drops in Orzhov colours seemed to be limiting her chances for cube use. Having now played with the card I am somewhat inclined to change my opinion of Kaya and feel that she easily deserves a main cube slot.

The key element of the card which i had misevaluated was the value and utility of her 0 ability. I had it down as something you mostly used on Kaya herself to either reset her loyalty or to protect her for a round so you can follow up with things to make her safe. In this light it doesn’t seem to do much to the board but the reality of the ability is that it is a far more versatile version of Kiora’s +1. In fact Kaya is all round like a better version of Kiora, the Crashing Wave who is herself very playable in cube.

Kaya’s first ability simply has so many applications that every turn you have an option to cast her or activate her you have to really think about what the optimal line of play is. You can target any creature, yours or theirs, for a variety of different reasons. Perhaps you are wishing to force through attacks, perhaps you wish to reset the level on something, perhaps you want to protect one of your own dorks from a mass removal spell or simply re-trigger its enters the battlefield effect. Just killing off a token is decent too! The scope of what you can do with it is greater than most other planeswalker abilities. It may not permanently effect the board but the control you have is so great with Kaya that in many ways she is better than just killing something.

It is the best protection ability on any planeswalker. It allows you to stop the scariest creature they have from attacking (or blocking) thus protecting both Kaya and yourself. Alternatively you can flicker out Kaya herself and make her not only completely safe from attacks but also any sorcery speed spells and effects that could kill her. One of my preferred ways to play Kaya is when they have a planeswalker and we both have creatures. That way you can take out a blocker and pressure their planeswalker without too much risk of a swing back threatening Kaya. In this way you gain significant tempo, hopefully some value while also having increased you ongoing options and threat diversity.

The -2 ability to draw and have them discard is also better than expected. Kaya is one of few planeswalkers you are happy to run into the ground to get the value as soon as possible. The comparison here is Jace, Architect of Thought. Frequently you lay that Jace and back to back -2 him so as to fill up your hand with gas. Kaya may give you a little less gas than Jace when used in this way but she deals a heavy blow to your opponent at the same time and is still alive with one loyalty remaining. At this stage you are not at all worried about having a vulnerable planeswalker on just one loyalty as she has already got you a four for one. There are not that many planeswalkers with a good enough -loyaly effect  combined with high starting loyalty that you can run them into the ground and feel like you got good value for mana. My other favourite opening with Kaya is simply to immediately -2 her. Ideally they need to have little to no board or overlap in creatures to do this but it feels so good when you do!

The -1 is the least useful early but you are glad of it later on. Having the safety of some life gain later in the game when you might need it allows you much more freedom to play how you want to in the mid and early game. This could mean generous use of Kaya’s zero loyalty effect, greedy Dark Confidant plays or whatever you need it to be. It is also a real winner against burn heavy decks where gaining two life is generally better than drawing cards. Late game having that potential reach for two damage a turn makes Kaya a pretty serious threat as well against any deck in which there is some kind of stalemate going on. It is like her ultimate except that you get to use it incrementally rather than only in one big hit. This further adds to the number of choices you get with Kaya and the complexity of playing her.

Kaya attacks on all fronts and affects most of the core resources in the game. Either she controls the board in your favour or she drains your opponents resources while powering you up equally in the opposite direction. Cards and life are important and Kaya interacts with them directly. As such there is no matchup in which she is ever a dead card. She always does something you want, often several things you want. Kaya brings a lot to the table and she does it for a relative bargain at four mana. Her drawback, if any, is that she is so much harder to use well than other planeswalkers. Each ability of hers has some cost, all of them can be useful right away and one of them generally has multiple viable targets and uses. You don’t ever get to plus her loyalty and so you have to weigh up risks every turn. It also takes a turn to reset her loyalty and so some planning for this is also wise.
Due to her being so direct in how she attacks and gives resources I can see Kaya being played in any type of deck able to support her colours. She is good for the aggressor, good in the midrange and you guessed it, good in control. Combo probably doesn’t have time for her but then combo rarely has time for any planeswalkers so no big surprise there. Kaya isn’t quite a top tier planeswalkers and probably sits just outside the top ten all time. Much of that is due to being a less playable gold card. Planeswalkers are really good in cube, more so than in most other formats, my cube is over 6% planeswalkers at a current count of 39. Being just outside the top ten planeswalkers is still a really good place to be. I highly recommend adding a Kaya to your cube. If not just for her awesome power then for her unique and enjoyable play style.