Overview
Ryuunosuke Yamaguchi was set to be the unfortunate last sacrifice of a cult seeking to bring Yamata-no-Orochi, the evil "Eight-Forked Serpent of Koshi" of Japanese myth, back into the world. But all did not go as his father planned; the priestess who managed to stop the sacrifice sealed Orochi inside his body; now Ryuunosuke and the demon are one. He retains much of Orochi's mundane knowledge from the past, as well as enough knowledge of the present from "The Boy" (how he refers to the teen whose body he's occupying) to get by. But he's still recognizable to those in the know; his trademark "eight heads" appear as seven holographic wireframe serpents on collapsible metallic discs attached to his spine by retractible metal arms (the eighth being his human body's head). Above all, he wishes to regain his former power. But in his mortal body, he has no idea where to start, and no idea what he would do if he could manage it. Watch this one, he's a snake. Literally and figuratively. But "The Boy" is still in there. Somewhere.
Perks
Serpent Heads< Edge >: Seven venomous techno-serpent heads that can entangle targets
Yamata-no-Orochi was known for having eight monstrous heads and eight serpentine tails. While he's no longer as large as "eight valleys and as many mountains", he does still have eight heads, in a manner of speaking. There are a series of seven plates attached to his spine via rectractible metal arms. These plates are about the size of a small frisbee when fully unfolded, but can fold themselves as small as a coin. When folded they store themselves along his spine in an overlapping row. When fully unfolded, each can serve as an emission point for a single holographic serpent head that appears to in wireframe. While they do appear holographic, they are indeed solid, and can bite and entangle targets within their effect range. EDGE: The bite of these heads can also poison both biological and electronic targets. This poison causes damage to biological tissues and can turn an electronic target's own security measures against itelf.
Secondary Heads Function: The seven "heads" can act as partially autonomous drones
When detached from their telescoping metal arms, the discs that the seven heads emanate from can fly to a range of about 300 feet to gather information. Any further than this and Ryuunosuke cannot maintain his real-time connection with them (though he can still retrieve them and download their information later, provided they aren't destroyed). They possess cameras and audio recording equipment, as well as IR/heat vision and seismic sensors -- lesser versions of his own abilities -- and the ability to interface with devices to upload/download information.
Hypnotism< Edge >: Mind games to calm victi -- er, opponents
Ryuunosuke can attempt to mentally pull an opponent's focus solely on him, and calm that opponent, appearing to make the world around a target seem to fade away, with a combination of soothing words and "soft" eye contact. This does work on machines as well, though differently -- his serpents attempt to introduce an algorithm into a target device that directs it to 'run in low power mode'. This can be broken by retrieving the victim or device from Ryuunosuke and either shaking them sharply (in the case of a biological/sapient target) or by entering in a normal use command (in the case of a device). Or by simply breaking Ryuunosuke's focus, as he must concentrate to keep a target under his spell.
Ye Old Knowledge: Mundane traditional Japanese skills mainly lost to time
Stemming from Orochi's existence during ancient Japan, Ryuunosuke knows how to make Japanese sake -- he is quite fond of the drink, even now if he's not technically old enough to partake of it -- weave baskets, plant/care for/harvest crops without modern farming machines, as well as how to dance in the traditional Japanese style.
Life Drain< Edge >: Drain energy from people and electronics
Ryuunosuke can drain lifeforce from people, or drain energy from machines. The mechanism differs whether he's draining life from a person or energy from a machine. For the former, he must be completely undisturbed, the person has to be docile. He "breathes in" the lifeforce, reminiscent of the old wives' tale of cats "taking a baby's breath". With a machine or device, a serpent "bites" into the device (this does not cause physical damage) and draws out its power.
Poison Lord< Edge >: Blood and bite -- everything is poison!
Ryuunosuke is both venomous and poisonous. Both poisonous chemicals and infective nanites swirl around in Ryuunosuke's blood. This makes it dangerous to be exposed to Ryuunosuke's blood whether one is biological or mechanical. While biological beings are generally safe as long as they don't ingest his blood, the infective nanites seek out electronic signals and data, attempting to "hijack" it. This does not allow Ryuunosuke to control it, but rather attempts to turn its own security measures against it, resulting in the nanites acting much like poisonous chemicals in a biological being. EDGE: He also creates poison for offensive use; this can be administered via either his serpent heads, or by direct bite with his biological head's mouth (though this clearly doesn't work on machines because he can't actually bite through metal with his mouth). The poison will begin to damage tissues within biological beings it's injected into, and will continue to do so until it is cured, or until the being can work it out of his/her system.
Serpent Senses: Sense heat and vibration, great sense of smell
Much like a serpent, Ryuunosuke has the ability to sense sources of heat and vibration, and has an excellent sense of smell. He can sense the heat of even a small field mouse up to several feet underground, and can feel said field mouse walking around from up to thirty yards away. However, when there are many heat sources together (such as people in a city), this sense tends to get confused and it's difficult to pick out a single heat source. Likewise, his vibration sense tends to be useless for pinpointing a single source of vibration where there are a great deal of people or beings in one place (again, such as a city). His sense of smell is almost more mundane... almost. He possesses a forked tongue and a Jacobson's organ, as a snake does, and is able to accurately analyze scent particles in the air with this sense.
Serpent Command< Edge-C >: Communicate with and command "serpents"
Ryuunosuke is able to understand and converse with "serpents". This is defined as not just snakes, but salamanders as well -- anything that is both reptilian, and that arguably "crawls on its belly in the dirt". However this does not include frogs/toads, regular lizards, or other types of reptiles/amphibians. This communication is on a mental level, and most typical animals do not have the will or mental wherewithal to resist his commands (unless owned by someone else or under someone else's control).
NPCs
Atsuta Priests< E-Tier Basic >: Holy babysitters to contain him or assist against evil beings
While Ryuunosuke's done nothing to warrant being destroyed, imprisoned, or otherwise dealt with permanently as of yet, that doesn't mean that the priests of the Atsuta Shrine are willing to just leave him to his own devices in the worlds outside. Ryuunosuke is generally accompanied by one of the priests of the Atsuta Shrine wherever he goes. These priests are all human, and all have the ability to contain Ryuunosuke with holy abilities if he gets out of hand. They may assist him in combat with those abilities as well, though they're not very strong, so it's usually better for them to take cover if the stuff starts flying.
Complications
Dark Aura: Tends to give people the creeps
Perhaps understandably, Ryuunosuke has an air of creepiness about him. While on occasion this can be beneficial, nine times out of ten it's just going to be a huge pain. It can be sensed even by people who don't have supernatural senses as the aforementioned "air of creepiness", and reads as sharply dark and negative to those who DO have supernatural senses. It makes stealth near impossible (because even if he can't be seen, his aura can be felt even by mundane senses), and tends to lean good people towards not trusting him unless he goes above and beyond in the quest to prove himself to them.
Altered States: Drunk, sedated, dizzy, etc., leaves him nigh-powerless
Concentration is not just a boon to Ryuunosuke, it's a NECESSITY! Spiked drinks, tranquilizer darts, even simple blows to the head, will result in a state that leaves him unable to use his more potent abilities with any degree of skill. He is left without the concentration to use his hypnotism, control his secondary heads, or regulate the output of his poison. As his physical disposition is not as powerful as it was when he was purely Orochi, this can leave him vulnerable in a very real way.
Evil Destiny: Without intervention he's probably going to end up wholly evil again
With the soul of Yamata-no-Orochi inside him, one might naturally assume that he's already as evil as he's going to get. But one would be incorrect in doing so. While the soul of Orochi is there, the soul of Ryuunosuke Yamaguchi -- the teenage boy whose body Orochi was sealed inside -- is also still in there. "The Boy", as he now refers to the previous human identity, does influence him in subtle ways. It's not strong enough to "cure" Orochi's evil by itself, though. Without the intervention of someone else, Ryuunosuke has no chance of escaping Orochi's evil.
Holy Symbols: These act as wards, and can actually harm him
Even if he's not wholly evil, the sharply dark/negative slant his energy now takes makes him vulnerable to holy symbols. He's unable to cross into -- or out of! -- areas so warded of his own volition, and in these areas he loses access to all of his abilities, save his animal command, until he is taken out of the area or the wards are destroyed. When placed on his person, these holy symbols immediately cease all effects he has in circulation (save for poison effects) and render his abilities unusable until it's removed. They also have a tendency to paralyze him temporarily when placed on his person.
Serpent Features: His face looks a little like a snake hybrid
It's almost impossible to hide that mug. While the features themselves are pretty mild -- blood red slit-pupiled eyes and a weird seam from the corner of his mouth to just under his ear -- the eyes alone are generally strange enough for most people to ask questions. Pair that with his unsettling aura, and it's just a very bad combination that is likely to not gain him many friends at first look.
Weak to EMP: Electronic devices tend to short out from EMP
Since Ryuunosuke does have cybernetic components, these components are vulnerable to being hit and shorted out by EMPs. While he can generally get them running again after a little while, it can still cause a hesitation that could cost him a battle... or worse. Of course, if his cybernetics go completely offline? He's going to end up getting knocked out.
Always Followed: He's not just being allowed to walk around unchecked
While he hasn't done anything to warrant being locked up, bound, sealed, and/or imprisoned (YET), that doesn't mean that he's being let to just wander around the world unchecked. He's generally always being followed by an agent from the Atsuta Shrine in Japan. This means that if someone else doesn't want other people knowing something, it's advisable not to tell/show this to Ryuunosuke. He won't necessarily tell anyone, but he might have a "shadow"...