At the beginning of your upkeep, Venser's Journal and Ophiomancer trigger.
Resolve the Venser's Journal trigger, causing you to gain at least two life.
Resolve the Ophiomancer trigger, creating a 1/1 Snake creature token.
Activate Razaketh by paying 2 life and sacrificing the Snake token, searching your library for Nexus of Fate and putting it into your hand.
Cast Nexus of Fate by paying ({5} magic symbol) ({U} magic symbol) ({U} magic symbol) , causing you to take an extra turn after this one and shuflle Nexus of Fate into your library.