Merlin is an Experimental Silver Tender Engine who believes He has The Power to Turn invisible.
- Season 14: Merlin the Magical Engine.
- Season 15: Nightmare on Sodor (fantasy;cameo)
- Season 16: Sweet Sixteen (does not speak)
- Season 17: Rocked by a Hurricane (mentioned)
- Saving Pirate Ryan (cameo)
- Merlin is The first Custom Engine in Keekre24's Series (not counting Ben who received a custom yellow wooden model in CGI).