One clarification up front: Act one is chapter [REDACTED] to chapter 5, i.e. where the game portrays Watcher as the protagonist, and act two is chapter 6 to epilogue, i.e. where the game portrays Blue as the protagonist.
When reflecting upon Knower’s actions during the game, I see some people arguing that Knower is part of the problem, an evil or at least morally questionable character, only interested in her own survival and thus somewhat self-serving, not worth keeping at the end, etc. I want to elaborate why I think Knower embodies in fact unmatched virtue within this story: She had the most to lose and the least to gain and still repeatedly risked everything to do what is right.
The above sentence might seem weird given how Knower tortures Watcher and takes her light, but in reality power always comes at a price. Even you, the player, are not free from this: You have the power to create a better society at the end of the game, however you need to use your power to kill Capital Red and the Red Guard. Otherwise, you end up like all absolute pacifists caught in a conflict with an opponent that is willing to use unrestricted force: oppressed or dead. But do you really think that all of the Red Guard are beyond redemption? Every single one? Do you truly believe that there is no single policeman in Hong Kong that is worthy of a chance at redemption? No CCP member? There are no good Russians? Every German, men, women, and children, after World War II was irredeemable? It’s an all or nothing deal, you don’t get to pick cherries with the Red Guard; and there is a good reason collective punishment is a breach of the Geneva Conventions. (1) The killing of any redeemable people within the Red Guard via collective punishment as a necessity to escape the cycle of violence is the burden you, the player, and Blue need to carry and the price you and Blue need to pay when using your power to create a better world.