[ Their sisters don't speak much to him either. They aren't in this world enough to care about it overmuch -- they instead sing to each other in a way that Vash can only sometimes hear, only sometimes understand. He isn't connected to them they way they're connected to each other, because he's an independent. A separate plant, more human than their sisters.

The plants who have joined with Knives, though, whose voices are filtered through him? Those he can hear, when he's close enough... as much as sometimes he wished he couldn't. ]

He wants everyone to die.

[ Knives -- adult Knives -- might have started off making grand speeches about liberating the plants, but Vash spent half a year imprisoned on the ship with their sisters, and he can say with certainly that Knives's aim is no longer about freedom from human oppression. He's amassing power for power's sake, and for revenge against the species who he feels has wronged him unforgivably. ]

Everyone was supposed to die when the ships crashed. This guy thinks he's just finishing what that accident started.

[ It's some of the truth, at least. A partial truth. ]