Naga Berserker, the main soldiers of the Naga race. As you can see, this guy is somewhat a tuned up male naga. With extra coating here and there. The weapon is crystal glaive held on some biomechanical staff.
The transformation from Oni to Naga brought some beneficial physical benefits. The increase of muscle mass and quantity in their body means that they become physically stronger then the other Oni, enabling them to take a more punishment, or in their case, more training.
A Naga society is a ruthless and yet honorable one. A Naga is trained to become a warrior regardless of birth. The training was brutal and seemingly inhumane. The Naga was constantly tested, sometimes pitted against impossible odds. All this training was intended to force the naga to adapt themselves, resulting in the massive increase in their muscle mass, and some of their scales were overgrown, forming layers of carapace around their body, creating some sort of natural armor casing for their body. And after the training ended, the Nagas were cast into an isolation in a specially made maze; an initiation procedure, where they were forced to fight for their lives against overwhelming situation. In fact, the training regiment was so brutal, only half of the roster would remain by the end of the day. Not only because some of the candidate may well be killed, but also because they' could've lost a limb or two, making them unable to become proper warrior. Thus the reason why all the candidates for the warrior caste are Nagas with sons and daughters to carry their name.
Transformation into a naga does not only bring physical merit, but also phenomenal increase in their psychic capabilities. Naturally, given their habitat, all Naga are water elemental chakra by nature. They say a water elemental master can produce water out of thin air. A naga took it to an extreme level: they can utilize water in every form and type. Utilizing the dynamic nature of the water chakra, they can create a dense water barrier around their body, protecting them from all sorts of hostile projectiles. The same barrier also enables them to stay outside of water for a longer periods of time, compared to their untrained brethren. Using their mastery of water, they can also manipulate the blood in their body, increasing their heartbeat, sending an abundant amount of adrenalin, enabling them to perform feats of inhuman proportion, and move with speed regardless of their increased size and mass. Lastly, they use Crystals (or Ice) in all their technologies: weapons, armaments, buildings. Everything was Crystal made. Needlessly to say, they're also an avid Water and Ice jutsu technician.
It was total bitter work. But the results were worth it: a Naga Berserker is practically a slithering all purpose weapon platform, capable of taking tons of punishment, and even better at dishing it out given that they're offensive oriented race. All the brutal training they underwent has shaped them into a ruthless, effective and efficient hunter killers. Merciless and thorough, a squadron of Naga Berserker (composed of seven berserker) could take out an army 10 times their own size without taking so much as a cosmetic damage.
But, regardless of all the power they boast, the Naga berserker is not without weakness. Like their other brethren, their effectiveness and mobility is somewhat limited on dry land. Also, being offensive oriented, they take little care in defensive techniques and they're heavily reliant on their barriers. If the barriers are wiped out, the Naga would find themselves in a rather disadvantageous situation where they become quite vulnerable.
And on a side note, they're still afraid of heights.