Christ is the center of the Book of Revelation. Christ is the one who communicates with John (taking the initiative to do so) in the opening chapters, commissioning John to write what he sees. Christ is the one who charges the seven churches, accusing them of sin and holding out hope for blessing (for most of them) if they repent. That Christ is central in the rest of the book is evidenced in that the themes and images of the first three chapters are opened up repeatedly in the rest of the book.
Christ is pictured as the one who rules. Christ holds the keys of hell and death in the opening chapter and is identified as the “First and the Last.” He shares the throne of God in chapters 4-5 and is the one who is deemed worthy to open the seals of the book and thus unfold God’s plan in order to bring it to consummation. He is also the judge that determines the destinies of all people, even heavenly beings.
Christ is also the Lamb. This word is used thirty times in the NT and 29 of these occurrences are in the Revelation. Christ is the Lamb slain whose death is the decisive victory over the enemies of God’s people.
Christ, then, is the ruler who rules with God’s authority by virtue of his having been killed and yet having triumphed over death and the Evil One. Because of this, he has the authority to bring God’s plan to completion including determining the destinies of all beings.