Nightshade is the name of the Thorn (semi-)organised resistance against the Cheshires.

While they're rarely able to make perfect use for them, Nightshade Thorns (or Thorns in general if they end up having the thought) are very fond of submarines for the obvious reason that being in a submerged submarine is great at giving them the power of not-dying.

Nightshade have a base under the ocean, with only minimal contact with non-watery bits. Said minimal contact is their own entrance into the base, and is equipped with a nice 'water-lock' for the sake of entrenching them in a lovely hi-tech moat. (That said, since Cheshires can be tiny if they want, this is not a perfect shield. But it's pretty good.)

Most of Chimera lives in the Thorns' undersea base – and you bet they are doing what they can to make sure it works again, because having enough of their sort around might be what decides this 'struggle'.

Note that just because the Nightshade Thorns are on humanity's side, it does not mean an individual human being should necessarily trust them. They are absurdly focussed on the 'all of humanity' aspect. Individual human beings are completely fair to throw under the bus to get there.