Complex sentence: During the Tanker chapter (the prologue of "Metal Gear Solid 2"), Revolver Ocelot stole RAY while it was transported in a disguised oil tanker and delivers the stolen prototype RAY to The Patriots, an organization secretly running the United States.
Split into simpler sentences: During the Tanker chapter (the prologue of "Metal Gear Solid 2"), RAY was stolen by Revolver Ocelot while being transported in a disguised oil tanker. After the events of the Tanker chapter, Revolver Ocelot delivers the stolen prototype RAY to The Patriots, an organization secretly running the United States.