@miyako19 I would say to the contrary, Nishina is dead, Lucas is the only personality I've seen occupying that body. To the point where if he's suddenly woken up he forgets entirely that the current world exists.
And really, him dying would solve quite a lot. As soon as he can't plot and manipulate events any more, whatever he's trying for probably won't happen. "Evil plots don't just hatch themselves, you know"--the world tends to spin off in unexpected directions, there are always events and interactions that change things, and without a live mastermind nursing events along things will diverge. Even if there really is some other manipulator behind him, whoever it is has finite resources. Without him, they'd have to expose themselves more directly if they wanted to affect events, and the good guys would probably notice.
Note that I'm not sure if that means I advocate actually doing him in--just that I think the reasons not to would have to be ethical, or perhaps revolve around not wanting to get caught by the authorities for murder; the claim that it wouldn't be
useful is inaccurate IMO.