Who is the last disciple of Christ?

Define disciple first. A disciple is a follower of Jesus Christ, or more accurately, a "bond-servant" (which is a more politically correct term for a willing or voluntary slave).

Therefore, the last disciple has not happened yet. Historically, John, writer of John, the letters of John, and The Revelations of Jesus Christ (Revelations) was the last of the original disciples (Apostles) living. Non-biblical account would place his death around the turn of the century, 100 a.d..