Diesel is the other main villian of the series, besides Gordon.
Devious Diesel is a black diesel shunter who is the member of the Big Bad Engines. He is friends with James and they say rude things to Duck (from Duck the Really Useful Engine) and Stepney (from Stepney the Really Useful Engine).
In 2012, Diesel teams up with Duncan, Daisy and Spencer to take over Sodor, so they push Henry under the coal hopper, push Peter Sam off the rails, call James Rusty Scrap Iron and give Toby a fright, and they race away to destory Sir Topham Hatt and office with bombs. But they come off a tight bend, hit the bombs and are destroyed when they are defeated by Thomas and Edward. After they are restored, they stay in the Crovan Shed for two months.