Research and basic principles
Orochimaru should have “lab accidented” that backstabbing, department stealing, green haired weasel while he had the chance. It wasn’t like he hadn’t considered it, the man’s plans for chakra enhanced mechanical weaponry were a disaster just waiting for an opportunity to happen. Just imagining what would happen if an enemy managed to scavenge some off a battlefield, and, sage forbid, duplicate them, it would be impossible to maintain control of distribution. Biological methods might be slower, and messier, but ultimately they were easier to control, no risk of incompetent chuunin and overenthusiastic genin accidentally leaving confidential weaponry on the battlefield if the weaponry was a part of their bodies after all. Orochimaru just didn’t understand how someone so obviously brilliant could be so very wrong. It had been infuriating. Nearly as infuriating as Verde’s constant refusal to acknowledge Orochimaru’s authority, which to be clear had been pretty bloody infuriating.
Yes Orochimaru really should have got rid of Verde a long time ago, it would have been easy, a quick substitution of some volatile chemicals, some judicious threatening of timid subordinates, and the whole thing could have been written off as an unfortunate accident. The weasel had been a thorn in his side since he first showed up in R&D with his insubordinate attitude, and his unsound ideas, and his irritating pest of a nin crocodile. Orochimaru swore that animal had it in for him, with the way it had kept eating his research projects, and oh so conveniently tripping him up when he was carrying dangerous substances, and giving him those looks that no reptile should have been capable of, and Orochimaru of all people would know.
He should have had Verde killed, discreetly, before it ever got to this point. But… it had just seemed so wasteful. The man had potential, if he could just be persuaded to the right way of thinking. There weren’t many scientists that could even begin to keep up with Orochimaru, and he’d been blinded by the novelty of having someone who was almost a challenge. Someone who could actually argue with him rather than just being demolished by his brilliance. Obviously he was wrong, but he was wrong in intelligent ways. It had been such a relief, to have someone understand the concepts he was working with without Orochimaru having to spoon feed it to them, even if it was because the two of them spent so much time shouting those concepts across the lab at each other, before retreating to run more tests, and mutter about progress and showing them all.
In the end, it wasn’t surprising that Verde had turned on him, his second had always had his own agenda and no loyalty to speak of. It was one of the things Orochimaru had liked most about him, even as he found it infuriating. He just hadn’t been expecting it to happen so fast, it had taken less than a day for Verde to discredit him. He hadn’t been ready, and the backstabbing weasel had caught him off guard. Going to the Hokage with evidence of Orochimaru’s less… ethical experiments had been a low blow, especially when he knew for a fact that Verde had no more scruples than he did when it came to the pursuit of knowledge. He knew exactly what sort of experiments Verde had been running in the back shed, the whole department did, and anyone who said energy weapons were less messy than biological augmentation hadn’t seen what Verde did to those bunny rabbits. Verde had just been smart enough to clean up the evidence when he was done.
Orochimaru actually found himself grudgingly impressed by how effectively his rival had managed to convince the Sandaime that he was the model of an ethical scientist. He just wished he’d thought to keep some evidence of what Verde had done with those prisoners of war and the chakra eating ray gun. Then he could have beaten the traitor at his own game, because that mess had been enough to give even Orochimaru nightmares. But Orochimaru had been careless, he’d underestimated his subordinate, and now Verde was busy running the department into the ground, while Orochimaru had to rebuild everything from the ground up.
Maybe it was for the best though. If he started his own village there would be no need to pander to the scruples of men less far sighted than him, no-one looking over his shoulder asking if it was right to run a particular experiment on living human subjects. He wouldn’t have to beg, and manipulate to get the funding he needed either. Yes, being exiled had been a blessing in disguise really.
And with the free reign running his own village would grant him he’d be able to prove once and for all that biological enhancement of loyal ninja was a far more reliable way of increasing a village’s military strength. Verde would see just how mistaken he was, right before Orochimaru had him killed. Preferably in a slow and painful way. Just because being exiled might actually be useful to his plans, didn’t mean Orochimaru was going to forgive the weasel.
Admittedly his earlier assassination attempts had been less than successful. For someone who had allegedly never been a front line ninja, Verde was suspiciously good at handling himself. But then again, considering who his classmates were, maybe it had just been a basic survival strategy. And of course while he was clearly deeply misguided he was he was intelligent. Almost a match for Orochimaru in that respect, so maybe he should have predicted that it would take more than an ordinary murder attempt to finish the traitor off.
He’d started with the basics of course. Poison in the food had been caught by Verde’s insistence on checking everything he ate for just that purpose, with a handy portable poison detection kit he’d invented. Bombs had also proved useless in the face of the explosives detection seals he’d had a friend devise on his behalf. Orochimaru had then resorted to sending in a series of shady characters with sharp edged weapons, only for them to be dispatched in ever more ignominious ways by their target. Verde was a menace with a beaker full of lab chemicals and that handseal free shield jutsu the man had devised was just cheating. Orochimaru wasn’t even going to mention the idiots that had managed to get themselves eaten by Kaiman, that had just been natural selection and was his own fault for hiring incompetents. But he’d even made a personal attempt during the chunin exams, and Verde had managed to dispatch his augmented shadow clone without even breaking a sweat.
If things continued as they were, Orochimaru might just have to get… creative.