the darkling and mal both represent ‘alina’s other half’ in ways that are utterly different and eerily similar, and i don’t think we talk about this enough tbh. we talk a lot about how the darkling and alina are two sides of the same coin, or how mal and alina are each others halves of a whole, but we don’t ever really talk about how these two things are both true at the same time and do not contradict one another whatsoever.
so the darkling is alina’s other half in the really obvious way right - he summons shadows, she summons sunlight. she is able to access his powers using merzost (which yes. is bad. not a thing she should do. that’s not the point); he is able to directly amplify her powers. they are two sides of the same coin with the way their powers work, yin and yang, in an intensely obvious way.
but they are also ‘one of a kind’ with their powers. they are, fundamentally, alone in the world save for each other. they are destined to live near immortal lives, and are the only ones who truly grasp how expansive that would be for each other, with their very specific powers. both are drawn to feelings of immense power; the darkling with creating and extending the fold, alina with that hungry desire for more and more power from the amplifiers. she decides not to follow him, she decides to turn away, but when it comes to these similarities, alina is a hair’s breadth away from choosing that path. hell, her decision not to and to try and turn him away is paired with her using merzost and essentially attempting to commit suicide were it not for mal rushing forward to save her.
the darkling and alina are the light and dark, they are the yawning chasm of unlimited power, they are eternal and unbridled power and glory. that dynamic is so engaging because of this.
mal meanwhile is also alina’s other half, but in an entirely different way. yes, they are each others halves in that they have loved each other since childhood, both wish they could run away from this war to live in peace together, and they would cross the world for each other - this is a basic ‘other half’ which is comparable to the darkling and alina being ‘light and dark’. but it goes far deeper than that.
he is the other half of alina in the sense that they are both ‘chosen ones’ to save the world; that power courses through both of their veins, and that power is fundamental to ending the darkness. you cannot bring about an end to the darkness with just alina or mal. alina’s light and mal’s amplifier blood (which gives him the enhanced tracking abilities which are also crucial to finding the amplifiers) are both needed to destroy the fold. in order to save the world, alina must lose her powers to pass those powers onto enough grisha who can collectively all end the fold completely; and similarly, mal must lose his ability to track, as the ‘second life’ given to him by being an amplifier must be killed in order for alina’s powers to pass on. these powers are so key to who these two are as characters, and you need both - and so naturally, it makes sense that both of them must lose their powers too, and come to terms with that together. they are ‘chosen ones’ who had no choice but to save the world and suffer great personal loss doing so.
where the darkling represents alina’s desire for power, mal represents alina’s desire for peace.
but where the huge similarity is (and this is why i never genuinely thought alina would end up with nikolai) is that both the darkling and mal were born that way to be alina’s other half in their respective ways. nikolai is a great character, but he doesn’t represent any part of alina’s inner longings, desires, or abilities - in fact, what he represents is a life at court, which alina hates. the darkling was born with his shadow abilities. mal was born with his tracking (amplifier) abilities. alina was born with her sun summoning abilities. all three of them were, in the basic fantasy trope sense, ‘chosen’ to play a fantastical, mythical part which to be honest? they had no choice but to do. i mean, for goodness sake, mal and the darkling are quite literally related, i’m not sure leigh could make it more obvious if she tried that these two can and should be compared narratively.
mal and the darkling may be about as different as it is possible to be, but the similarity they have is that they both represent the two paths for alina. not in the sense of ‘who does she love more’, i’m talking much deeper than that. they represent a path of power and darkness, and a path of peace and ‘saving the world’; and the thing is, alina is drawn to both of these pathways in the trilogy. alina yearns for both things, and that is what makes her dynamic with both of these men so fascinating and so well written. it isn’t about which man ‘completes’ her - alina is very much complete by herself. it’s that both men represent the other side of her, the side of her dreams and desires, and she could very easily tip from one to the other.