The first thing a principle does is kill somebody, and a cynic is only a frustrated romantic: That Godawful Mess About Being Friends with Lily.

Lily was: Beatrice, Dulcinea, Melpomene, Irene Adler, and also Gawain, for a while, to his Arthur, his Green Knight, and his Raganelle (he hoped for longer that she would, like Gawain, repent of her weaknesses and callow superficialities, but she instead became convinced they were strengths).

Medieval kings were at once, to their subjects, both peerless specimens of nobility, chivalry, and gentilesse and ruthless, carousing, politically savvy cold-or-hot-blooded killers not to be crossed. So Lily had two faces to him, neither far away while the other was showing.

She was very near an ideal of womanhood, the Maiden's avatar on earth, with her vivid beauty, her vitality, her love for beauty in the world, her competence and power, her desire to elevate and protect. She was also a bloody annoying best friend to have: impulsive and demanding and, in her more earnest and more liberal way, at least as arrogant as any of his Slytherin friends. She was just as sure as they were that not only was she was right but that others were wrong, and bad.

Severus usually thought he was right, too. He'd been born under Janus into a souring household, though, and knew earlier than most that truth is multifaceted and subjective, causality circular.

She was his favorite person to spin magic and theory and philosophy with (until it got personal, which never went well) and the only person who could keep up with him in the stillroom and challenge him in Charms without resulting grievous bodily harm. But she wanted him to change himself. He must become someone to suit what he felt to be completely naïve ideals unattainable to someone with his position in the real world.

She made him long to be a better person—no, really, she made him. He was unable to defend realistic choices around her, was left admitting that yes, it would be better if such and such could be different, left foundering. Not only was he unable to bare the green secrets, but he found himself stumbling over what he might have said, unable to articulate the politics that would explain to her why these things could not be different now, left bitterly wishing they could so he could live in her dream world and fit there.

To Severus, clutching his soul's unformed integrity like a rather spiky life-jacket in a drowning sea of blood and bone politics with quicksand on one side and gators on the other, her evangelism was more than a little unforgivable. He wondered bitterly (along with those few who didn't just dismiss him as a creep or a hopeless case with a hopeless crush) if he should have been a badger: he always forgave her anyway, when she wouldn't even try to understand him. Lily would only endure what she found grubby, or wouldn't.

Guinevere Lily was not* to him, nor Isolde, no matter what Potter feared and Black thought. No matter what filth Severus would spout to Tom Riddle to explain his known interest. He would have brushed her hair happily and even with reverence for the honor of the intimacy, pulled the moon out of its reflection to present to her on a platter of paper-thin alabaster, gone into the most sickening of battles with her favor under black robes to chastise him, killed and died and put away his cauldrons and refrained from evil to be tortured and taken apart himself if he'd thought it would do any damned good.

If he'd been a different sort of man, one who wore his heart on his sleeve because he wanted to and thought it right, any suggestion that he hadn't loved her would have resulted in an instant percussive loss of teeth. One might even have said he was in love. Certainly he was by any standards of classical romance or chivalry.

Some love, though, precludes desire. It can't simmer in the hearts of every pair of best friends, not even the most devoted, not even in the heart of the one who loves most deeply, more deeply by far than does the beloved, and knows it. Not every need to chase and hold and never let go, not every jealousy comes from a sweaty yearning to share skin. Everyone knows this, on some level, who's ever stayed up too late for their age because they can't bear to be left out of the mysteries and antics the family might get into without them.

It was a betrayal, undying serpents roiling in his heart, that she could bear to date his tormentor, let alone be enthusiastic about it and pretty much completely fail at using her influence to protect him. Yes, she said 'no more' but then she just assumed she was obeyed, until an incident tripped over her. This repudiation by his first master might not have been responsible for his quickly-regretted oaths to his second,* but it certainly made them simpler and more natural.

It was also revolting that a man might touch her, an outcry against heaven and earth (being intellectually aware that one's muse is a human person with human hormones of their own just doesn't help in these situations). His disgust and despair at her taste and lack of judgment, at her allowing her lust to overcome her usually quite annoying righteousness and the good sense he missed, and at the corruption of her sense of humor, had nothing to do with her not wanting to be with him.

He would have been long over envy even if she hadn't been Diana to him, even if he hadn't had someone of his own, someone a hell of a lot more touchable and comfortable. Someone who really did like him for himself, who unaccountably wanted him, who knew how to use him to their mutual advantage. Someone who was, in short, all a Slytherin could desire in a partner and swordbrother, while the choices were easy enough for personal loyalties to survive.

No, even if things had been different, he wouldn't have wed her. She only liked him for what she thought he could be if only he would be completely different, and wanted to remake him in her image. He'd seen firsthand, fist first, what the refusal to let a spouse be what they are could do to a marriage, and do to its children.

He wouldn't have kissed her, either, not the Maiden, not his white shadow, not that infuriatingly self-righteous nag. Would never have, except on the flaming waterfall that served her for hair, except laughingly on her white and freckled hand, except to close her cold, cold eyes.

*If she was a Guinevere, then logically not he but Black would have been aaargh, aargh, bad image, brain bleach, obliviate, obliviate!

* those had been almost inevitable from the moment his Gryffindor mother was disowned by her Gryffindor parents for, essentially, choosing her life heart-first with full conviction (otherwise known as being a Gryffindor). Their inevitability had been set in stone when his Sorting had sealed the deal and stopped even the stream of small gifts snuck to her by her mother his birth had begun and news of his first magic had strengthened.

Notes:

To me, writing this chapter was like ripping the shell off a live crab and aiming a sunbeam at it through a magnifying glass. It frets and upsets me. For one thing, there were are so many more interesting ways to interpret the prompt: Casanova had much more in common with Our Antihero than the trope attached to his name would suggest. Why, then, gravitate to Lily? Because it's obvious? Not really...?

The character dissonance that necessitated settling for the obvious is that Casanova was, at least at according to himself, intuitively good at the very things Severus teaches-and-can't-do-or-even-imo-really-wrap-his-m ind-around-even-though-he-can-probably-recite-the- rulebook-from-memory. He was such a better Slytherin than Severus is (although not nearly as good as Severus would like to be or has convinced others that he is) that I just couldn't make it work.

I'm including, at the bottom, alternate prompts I could and should have gone with, and if anyone manages to get anywhere with them, please let me know. I recommend you to read them even if you skip my prose: these are interesting, cogent, and relevant quotes from a man more fascinating than his two-dimensional legacy leads us to believe. All I, for example, knew about him before this, was that he was a lady's man and probably the suave sort of sleaze. Maybe you knew he was a spy; I didn't.

Back to the point: many people reacted somewhat less violently to the Prince's Tale than I did, and some even with pleasure, and if you, gentle reader, are one of these, then this is my gift to you.

On the other hand, if you were as appalled as I was at what JOdel at Red Hen Publications (who is brilliant, and I hope I have her name right) called the 'badly-fitting personality transplant' that 'rendered [Severus] down into nothing more than Merope Gaunt lite,' then take this chapter as it was written, not posted: as some attempt at reconciliation (I seem to make these), not especially satisfactory, between what the character's creator inflicted on him and what has made him, to so many of us, more than the nasty little grinch and creepy stalker she evidently thinks he is.

Quotes from Casanova's Writings I Probably Should Have Used Instead

I took the most creditable, the noblest, and the only natural course. I decided to put myself in a position where I need no longer go without the necessities of life: and what those necessities were for me no one could judge better than me... No one in Venice could understand how an intimacy could exist between myself and three men of their character, they all heaven and I all earth; they most severe in their morals, and I addicted to every kind of dissolute living.

Thus did God provide me with what I needed for an escape which was to be a wonder if not a miracle. I admit that I am proud of it; but my pride does not come from my having succeeded, for luck had a good deal to do with that; it comes from my having concluded that the thing could be done and having had the courage to undertake it.

What has infused my very blood with an unconquerable hatred of the whole tribe of fools from the day of my birth is that I become a fool myself whenever I am in their company."

"he man … must be a chameleon sensitive to all the colors which the light casts on his surroundings. He must be flexible, insinuating, a great dissimulator, impenetrable, obliging, often base, ostensibly sincere, always pretending to know less than he does, keeping to one tone of voice, patient, in complete control of his countenance, cold as ice when another in his place would be on fire; and if he is so unfortunate as not to have religion in his heart he must have it in his mind, and, if he is an honest man, accept the painful necessity of admitting to himself that he is a hypocrite.

The same principle which forbids me to lie does not allow me to tell the truth.