So this is some kind of different Parasitic relationship? Like, it eats away the host's nutrition or life force faster or something in exchange for stronger control over the body or something
It's interesting because it shouldn't have needed that before now?
Like if I were to rank the hosts by how much control/strength/tendril power they require it'd be:
1. Stella
Wide gap
2. Stepbrother
Medium gap
3. That advisor guy
The advisor should have been a relatively cushy host* because he probably doesn't deal with a lot of life or death situations and he can order people to do his bidding.
Doesn't seem like the author is setting up a, "all parasites age wear out their hosts," kinda deal so this new parasite either drives hosts like it stole them or it saps at its hosts lifespan even when doing nothing.