Although Mara is the goddess of love, she is never mentioned in association with Love, the path to Amaranth. In all of C0DA, the Loveletter, and the 36 Lessons of Vivec, her single mention is as MHARA, one of the eight known worlds of the Dwemer - who do not know Love. This curiousity has intrigued me for years, and has inspired the thematic subject of many of my apocryphal texts. I have come to believe that Mara is never mentioned because her love is the opposite of the Love of Amaranth. To understand this, let's take a look at the divisive nature of Amaranthine Love and Mara's role as the perpetual approach, or the force of attraction in the Aurbis. Further, let's think about what this means in the context of C0DA.
The Nature of 'Love'
The best definition of Love as laid out by the Loveletter and the Lessons comes from http://hermetic.com/crowley/little-essays-towards-truth/love.html by Aleister Crowley*:
"Love may best be defined as the passion of Hatred inflamed to the point of madness, when it takes refuge in Self-destruction.
"We begin to see the first inkling of emergence, which by its nature requires the merging of two-fold powers. Inevitably, this leads to another gradient..."
Although the association of this state with freedom may seem odd at first, I think it makes complete sense. For http://www.classicreader.com/book/92/363/, to imagine someone completely free we must also imagine them in utter isolation.
This doesn't seem much like the love we normally think of, does it? That is because it isn't love at all**, but a rather nastier concept that has hijacked the word 'love' as a vector. Crowley states this explicitly:
"There is then little indeed in common between Love and such tepid passions as regard, affection, or kindliness; it is the uninitiate, who, to his damnation in a hell of cabbage soup and soap-suds, confuses them."
The Role of Mara
This brings us, at last, to Mara. She is the goddess of love, and, per the above, a demon of cabbage soup and soap-suds. Her priests in Riften describe her domain thus:
"Mara's domain encompasses the emotions we strive the most to embrace: love, compassion, understanding."
Metaphysically, she is linked to the Dawn:
"We are devoted to the goddess who gave mortals the gift of love, that they might have a hint of eternity." "To love is to know the true nature of the gods." "Not all can hear the broadest echoes of deepest Dawn." "The Dawn surely opens upon you."
I believe that all of these elements are manifestations of one thing: the metaphysical impulse of disparate elements to perpetually approach one another. Understanding is our approach of another's thought; that is Mara; that is love***. As this force of attraction or impulse of approach, Mara reminds mortals of the Dawn, when gods and mortals were conjoined in transcendental intimacy. She is half the mechanism of the kalpic cycle: Mara's love pulls the world back toward Dawn, where it is inevitably sundered once more to begin a new kalpa.
This sundering is the goal of Love, which merely exploits Mara's sphere for the furtherance of Freedom and Amaranth. If there is a spirit that embodies this impulse to sunder, I think it is Kyne/Kynareth. Associated with Freedom through Alessia and the common symbolism of the sky, she can be thought of as sundering, or the impulse to issue: whereas Mara embodies gestation, Kyne embodies birth or expulsion. See this clearly in Alessia's words to Kynareth from the http://www.imperial-library.info/content/song-pelinal:
"And this thing I have thought of, I have named it, and I call it freedom. Which I think is just another word for Shezarr Who Goes Missing... [You] made the first rain at his sundering [and that] is what I ask now for our alien masters... [that] we might sunder them fully and repay their cruelty [by] dispersing them to drown in the Topal."
Whereas Mara is the mother of earth, Kyne is the midwife of nature's bounty and of rain: earth and sky's issue, sundered gravidity. Together, these spirits form the metaphysical dichotomy of freedom and necessity, Love and love.
What does this mean in the context of Amaranth and C0DA?
Let's think about Anu as Amaranth before we tackle C0DA. After the death of Nir, Anu slept in the sun and dreamed the Aurbis as we know it. He achieved Amaranth by submerging himself in catatonic isolation and sensory deprivation. Now, although it isn't the origin of her name, there are many examples in RL mythology of sleep demons known as 'Mara' or some derivative thereof. This is the origin of the word 'nightmare.' These spirits sit on people's chests while they sleep, pressing them down and giving them bad dreams, and are probably inspired by the phenomenon of sleep paralysis. Sleep paralysis occurs in the hypnagogic state, causing a temporary inability to move and, sometimes, horrible hallucinations.
I think that Mara is thus the nightmare of Anu. Anu fled his horrid reality by isolating himself in sleep, but Mara's perpetual approach does not allow for such denial: she threatens Anu with the paralysis of his freedom and terrifying memories of whence he came and what he might have done. Although the spirits of Anu's dream may see her merit, such is his fear of her that he has attempted to replace her love with Love, avenue of escape, and to use this as a vector to displace her throughout his unconsciousness.
This brings us to C0DA. Much like love is merely used as a vector for sundering and isolation, I believe that C0DA also spreads division. Although the ending of C0DA employs imagery of unification (the healing of Lorkhan's wound), I think this is an illusion - for as we have seen from the Loveletter, Amaranth is inherently isolated, individual, 'God outside of all else but his own free consciousness...' The achievement of Amaranth does not unify, but rather shatters the Aurbis into an infinity of alternate Aurbises, each corresponding to an independent interpretation. Thus are all of our interpretations made True - we all access separate, alternate Aurbises.
We can see this division in the aftermath of C0DA - in the tendency to plunge deep into our personal headcanons without care for what has been said before or what others say now and in the very controversy over its meaning.
Is this really how we should approach lore? Should we submerge ourselves in sensory deprivation, hallucinating our separate Aurbises without care for or attention to the visions of others? Or should we embrace love, and do as Mara would have us: listen to each other, attempt to understand one another? Should we divide, or integrate?
Should we Love... or love?
*Crowley's relevance is supported by the first http://www.imperial-library.info/content/fireside-chats.
**or not that type of love, if you think it comes in types.
***For more detailed in-universe discussion of both love and Love, see http://www.gamesas.com/topic/1430037-decretal-dehiscent/#entry21929418 and http://www.gamesas.com/topic/1443737-tsirelsyns-bound/#entry22249308.