Which Star Trek film introduced the character of Shinzon?

Star Trek: Nemesis introduced the character of Shinzon.

Shinzon is a human clone of Jean-Luc Picard and the leader of the Reman forces in the film. He was created by the Romulans as part of a plan involving Picard, but was eventually sent to the dangerous mining world Remus, where he rose to power.

Tom Hardy played Shinzon opposite Patrick Stewart’s Picard. The central conflict explores how two genetically identical people can develop radically different identities under different social and political conditions.

Shinzon is unique to Nemesis and should not be confused with other Star Trek antagonists such as Khan, Nero, or General Chang. Nemesis also introduces the Reman warbird Scimitar and concludes the theatrical film series focused on the Next Generation cast.