While healing Rinosus, Nova tried to think of a plan to keep this guy under control. He didn't have any such technique for doing this, so he did what any man should do at some point in life, ask a woman for her expertise.
'Fiona, do you know some technique for controlling others, or to at least not get betrayed?' Nova asked this without much hope. He realized that this type of techniques must be rare.
And he was right, they were very rare, but who was Fiona? 'I know a simple one that is mostly used by everyone, even outside the Zones. It's called Soul Pact. It allows party A, that is you, to receive a part of party B's soul and bind it.
If party B ever tries to scheme against you, they will be punished by the rules of the Pact between you. So it's one of the most popular and easy to use technique of this kind. Of course, there are ways to go around these rules, but at least here, you don't have to worry about something going wrong.'