This is how I thought your ability will look like. It's kind of how Demon Snow appears but not quite.
Her strings are invisible, the victim can't see them but the user can. NSA (No Strings Attached) will emit a gas into the air, whoever breaths it in can be controlled. NSA will whisper commands into the victims ears and once the victim is unusable they are then killed.
(Rips the puppet version of that person and that's how they die)
She can only control one person at a time and can't control another person until that person died or the user calls NSA off.
If that happens NSA can still have a puppet of that person and call them anytime.
((I drew the art))
No Strings Attached was a ability name in a one shot I saw and belongs to that person. The only thing I own is what the ability can do and I tweaked it up a bit. So whoever made this ability credit to them, I don't remember there names but credit to you.