Kinbote weaves into his footnoted annotations on the poem the story of his own relationship with the poet, John Shade. ... Revolutionaries who sent an assassin to hunt him down, an assassin whose bullet, meant for Kinbote, mistakenly killed John Shade instead.

Who shot John Shade?

It's possible that Shade really was killed by the madman John Grey - but Kinbote suggests that he induced the man to confess, which could easily mean that he induced him to falsely confess (and perhaps murdered him or at least slipped him the razor blade so that he couldn't recant).

Does Kinbote kill himself?

Kinbote's second story deals with King Charles II, "The Beloved", the deposed king of Zembla. ... In an interview, Nabokov later claimed that Kinbote committed suicide after finishing the book.