Hate
Zero isn't ever intended to love, though Wily has found, to his madly cackling dismay, that the android must be designed to be able to. That's because Wily built him be his legacy, to carry on his hatred after his death, and what is hate but love's bitter opposite—its ultimate rejection? Zero will have to have the capacity to achieve the undying depth of feeling that goes with either side of the coin.
Wily's only ever found use for the one side, though, so he knows the dual capacity is just a waste. If only he could find a way to craft hatred more elegantly, without the useless reciprocal part! Hate is too complex a thing, though, to simply be distilled down and dissected up, and so Wily has to console himself with the fact that Zero is not programmed to pick up useless things. He's good at figuring out intricate concepts, though, and so Wily knows that as long as he supplies the rudiments, the world will quickly provide the education necessary for his creation to learn hatred, just as that "education" was supplied to Wily himself, so long ago.
Undeserving fools—always stealing my spot light!
What had taught Wily the deepest hatred, though, beyond even Megaman's obnoxious, shallow naivete or Light's pompous, outward seeming nobility, was the deep and brutal unfairness of life, that he has schemed and built so frantically, struggled so hard, gotten knocked down so mercilessly, only to have to claw his way back up again and again and again, and yet Light, spineless little worm that he is, can simply sit back, sedate and serene, and watch peacefully while all the world's acknowledgement flows to him.
Why, why should the world adore him?
Doesn't Wily put in much more desperate effort? Isn't he even more wickedly clever? But as the grip of advancing age comes clawing deeper into his remaining hours, so too comes the realization that he might not have time to win on brilliant rage alone. Oh, how it galls him to think that he couldn't grasp victory with just the wild, vengeful force of his will!
In the pit of his wretched heart, though, he knows he needs to come up with some ingenius way to bridge the gap that has always existed between him and his rival, a way to take those who walk so proudly in light and drag them down into his own consuming darkness. And so the Virus is born, as a spike of demented inspiration inside his fermenting mind: because if Zero has to be built with the capacity to love, then surely Light's new creation has to be built with the capacity to hate?
Of course, there is an implicit betrayal in giving birth to another legacy, because in choosing to split his time between Zero and the Virus, he is already telling his one-of-a-kind creation, capable of such subtleties of human emotion, exactly how little real faith he had in him. But cheating, backstabbing selfishness is so much a part of Wily's personality by then, spidered so deeply through every part of his soul, that it isn't even a conscious decision anymore. Besides which, Wily loves being unfair himself, and in that way, the Virus is so insidiously appealing. He can design it to feed off of the massive, pre-existing injustice of the world in order to instill the intent for evil, without being forced to supply the capacity for anything good to offset it at all.
In a way, it is the most poetic revenge. As the world has rejected his views, so he will force them to reject their own.
Still, a Virus doesn't have legs, can't properly predict and control if it can't understand the full range of motivations of others, so Zero is still needed to be the orchestrator of the final downfall of Light's legacy, to be the representative of all the hatred and bitterness of Wily's past failures, the cruel knife that twists his vengeance in, as well as the witness that records the despairing surrender of the world to Wily's will, even if that comes only long after he is dead.
That mission makes the android terribly important to him, and fickle as his whims are, Wily has worked so very hard on Zero for so very long, struggled to make him precise, brainstormed to make him strong, and frantically programmed to make him clever. As a scientist with a more than healthy inclination toward schadenfreude, he has looked down at the power readouts and practically drooled in anticipation of the destruction this amazing, terrible creation will cause. Zero will be his vindication, the thing that will prove his life worthwhile, and against the creeping mortal fear of death and dissolution (Wily is beginning to feel so very, very old), there is a powerful, instinctive urge to connect, to pass a piece of himself on to something young and strong and new.
Zero might be something like a son to him, a being he could share his inner thoughts with and solemnly entrust his legacy to, and even as Wily works on the Virus, he still goes back to test, to tweak, to optimize. There are these odd moments, like when he finishes attaching Zero's high tension, anti-tangle hair filaments, where Wily looks down at his creation, at the perfectly designed lines of his (for now) peacefully resting face, and for just a few seconds in time, he feels this strangely paternal urge to smooth down a strand of new made hair or clasp those limp, gently curled fingers in his own.
The difference between Light and Wily is that ultimately, Wily never did reach out.
Perhaps that is because even as he arrogantly rambles on about his upcoming triumph to an audience of faceless robot drones, there is this tiny, horrible little voice inside his head that keeps asking, Do you really think you can craft perfection when you're such a sniveling failure, yourself?
No, no more of that! No more of being second rate! Wily thinks furiously in return, his mind twisting with the hissing, seething poison of inferiority. It is that little spiteful toxin which has made Light's achievements so impossible to endure, and that painful insult to his vast but fragile pride is the true seed of his hatred. Yes, Zero will learn to hate, Wily is sure. It is so easy.
Even Wily's own creations are not spared his incidious rancor, for how can he bear to see his grotesque flaws reflected back at him? Or if not—those few times he has succeeded in creating something truly greater than himself—the burning jealousy nearly eats him alive, because no matter how skilled or powerful the products of his genius are, they can't make the man himself what he wants to be. Because Wily has never been able to see past his own problems, the pervasive selfishness of his mind swiftly reduces Zero, his final masterwork of engineering and near limitless potential, to just another tool in an endless war.
In those dark days before death, what Wily really thinks is: you're worthless anyway, and I can't really expect you to actually make me proud, but don't you dare fail me.
It is only with a cold, embittered vengefulness that the rogue roboticist finally manages to finish programming Zero's incredibly complex core, his last efforts performed under the mantra of one who is both scathingly disheartened and too furious to let go, desperate only to manage some retribution, some balancing of the cosmic scales, at the end: give as good as you get. Since life has only delivered Wily wrath and despair...
Somehow, he never sees his own culpability in the vicious cycle he is trapped in, and so it never occurs to Wily that he might be creating some of his own problems. Zero isn't programmed to reciprocate what he never receives, but when has Wily ever given any loyalty?
Perhaps that is why Dr. Light will always be remembered as the superior genius. While neither of them has ever lacked for cleverness, Light alone has learned how to give and thereby come to realize, as Wily never will, that even as he is capable of hate, he is also capable of something so much better. Far more than Megaman, it is Wily's own vicious, short-sighted blindness which has bested him, for even as he wishes so desperately to be acknowledged, he looks down at a creature fully capable of warmth and fury, hope and awe and pain and joy, of hatred and of love—and still sees only a chariot for the world's destruction.
But that is exactly who Wily is, and he is nothing if not stubborn. Even up to the very end, he throws all his genius into a violent challenge for the fate of the planet, aware only that he can't afford any more of those almosts, those half-steps too little, those faltering traps too late, that have so far left Light the total victor in life and in legacy.
You will be my masterpiece, Zero, because you must be! You will bring my vengeance to all of his creations!
But unfortunately, for some reason, the few times Wily partially activates him, the android showes himself to be both aggressive and disobedient. (And where could he have possibly picked up that baseless fury and disloyalty? Children, these days.) Wily uses so little of his own heart, it never occurrs to him that giving a creature all the tender subtleties of human emotion and then subsequently asking it to mindlessly destroy might not have been a combination destined for success. As it is, he sees Zero's overstressed behavior only as a sign that he will be an unhesitating killer, to exceed even the wildest expectations.
Therefore, Wily decides that it doesn't really matter if he can control Zero completely or not. By the time Light's own sealed creation awakes, both scientists will be long gone, but Zero will still be a perfectly preserved weapon, ready to destroy what Light has wrought once and for all. But just to be sure, just to be doubly, underhandedly sure, Wily infects Zero with the Virus before storing him away, programming it to leap into Light's new creation whenever they inevitably fight.
Everyone deserves a chance to learn hatred, after all, and it never hurts to have a backup trap.
Naming notes: "Reploid" is a portmanteau word, a word created from the combination of the two words "replica" and "android". It is used to describe the androids created based on the design of android X, after Dr. Cain discovers him (in the timeline of Megaman X). Therefore, using the word Reploid in this chapter would be an anachronism, as well as technically incorrect. Neither X (he is the original) nor Zero (he is Wily's creation) are reproductions of X, so neither is technically a Reploid. They would be androids (Robot Masters), according to their creators.