Yakra XIII is a monster found in 1000 A.D. in Chrono Trigger. He is the "boss" enemy the player must defeat in Guardia Castle after recovering the Rainbow Shell. He is also the descendant of Yakra.
Yakra XIII disguised himself as the Chancellor in order to take over the Kingdom of Guardia. But when Crono's party discovered the evil plot, they faced Yakra XIII and defeated him.