Nura

The Nura clan was a clan of ninja that existed long ago, before Kaguya Otsutsuki's time. This clan specialized in stealth, and was used as an assassination mercenary group. However, after Nenshu was passed on to the world, the Nura clan gained a special power they call the Demon Pulse, a power that allowed them to use demon like power. The Demon Pulse increases the user's strength and speed passively, but also allows the user to create a purple flame unique to the clan, and emit it from their hands, feet or whatever they are touching, allowing them to further enhance their fighting capabilities. It also gives the clan the technique called Uchinaru Kurayami, which is an ability that allows the clansman project their inner most power, a power that is unique to an individual from the clan (For example, if someone's personality was hot tempered, their Uchinaru Kurayami would engulf them in flames, allowing them flight along with other perks). The Uchinaru Kurayami can only be used once in a while, as it takes all the chakra from within to use, and would need time to replenish all the lost chakra. The Uchinaru Kurayami can also only be used by elite members of the clan. The Nura clan also makes a drug for their members that boosts the user's strength, speed and perception greatly. However, the drug is dangerous, as it not only is highly addictive, but using too much of it at once would cause cellular degeneration, the complete loss of chakra and eventually death. This drug is only used if the clan member is in a spot where they have no other option and is usually kept on person hidden, so the enemy could not take it.