Diesel 10

Diesel 10 is a fictional character in Thomas & Friends, he is the series's primary antagonist

Diesel 10 was going to be the secondary antagonist in Thomas and the Magic Railroad before P.T. Boomer was cut from the movie, he was neutral in Calling All Engines and The Great Discovery, he played a minor villain in Misty Island Rescue and the main antagonist in Day of The Diesels

Facts

Diesel 10 is probably the most evil villain of Thomas & Friends having damaged Lady, damaging the Sodor Steamworks and threatning Thomas, Bash, Dash, Ferdinand and others at the Sodor Search and Rescue Centre

He, Splatter and Dodge were the only Thomas villains before 2011 since even if Spencer was a real villain, he became good at the end of Hero of The Rails

Diesel 10 is probably the only supervillain of Thomas and Friends