Kana

Thousands of years of history prior to the arrival of the Ars, there were ancient practices and societal developments that the warriors of eld had to quell or understand in order to address establishing peace among their settlements. Despite these efforts to teach and avoid criminal activity, when the Ars came, new laws were placed. Some of these new laws addressed issues the Ara were facing years prior, but worded in a way that seemed detrimental or too vague to provide any support to the growth of their people.
One of these laws is that regulating the Kana, a specific group of individuals with ancient history, known more by individual practice than by a stable network, due to the methodology tied to this specific profession. The Kana are distinctly marked as illegal in both the terms of the Ara and the Ars, and seems to be one of the few things the people originally of the Framework as well as those trying to assert control can agree on. This is due to the nature of the Kana, as their practice is tied to assassinations' work as well as any acts of active vengeance-seeking.
To hire a Kana is to actively commit a murder. It's no mere form of association, the work of the Kana involves channeling the energy of malice into a workable form and taking out targets. The Kana take the visage of beasts of the night, and track the quarry assigned to them for as long as they are physically able, and will complete the contract and slay the person involved that was requested to be assassinated.