Cecil is a waiter at Dot's Diner in Mainframe. He is shaped like a video screen with a pair of arms, he has no legs but hangs from a pole that slides on a track in the ceiling. Cecil's format is a Dedicated Server. He has a french accent and has a thin mustache and bow tie. Cecil's icon is rainbow color rather than the traditional black and white. (The Tearing)
Although almost everyone pronounces his name Cee-Cil, he has repeatedly asserted that it is actually pronounced Ceh-cil. Unlike everyone else, Dot pronounces his name correctly.
Cecil is incapable of leaving the diner without help. When a Game Cube drops on the diner Cecil is carried out by one of the people in the diner in order to avoid the incoming Game. (AndrAIa)
Mouse and AndrAIa searched the ruins of the diner and found Cecil. They attached his upper bar to a Zip Board so that he could move without the track. His arm was injured and was placed in a sling. Cecil was brought to the Principal Office where he was reunited with Dot. She was very happy to see Cecil and gave him a hug, but he didn't want to show such emotion in front of the customers. (To Mend and Defend)
When Mainframe began to crash, Cecil was evacuated to the Principal Office along with the rest of the city's population. He was seen serving drinks to some of the city's inhabitants, including Mr. Mitchell, Old Man Pearson, Binky, and Algernon. They were getting drunk and throwing glasses at him. Cecil lost it and left the room. (End Prog)
After the city was restarted Dot's Diner was restored. Cecil returned to work at the Diner, serving as much criticism as he used to. Mouse did not care for his remarks when she hurriedly asked for the check and sliced his bow tie with her katana. (Cross Nodes)
When a fake Bob came to Mainframe he asked Dot to marry him. She asked Cecil to be her wedding planner. Dot and the fake Bob wanted to get married in the war room but Cecil protested and said they had to get married in a grand room like the Principal Office's main Entrance Hall. Cecil did a wonderful job creating a beautiful wedding despite the fact the wedding failed. The fake Bob was revealed to be Megabyte in disguise. The beautiful wedding hall was destroyed in the ensuing fight between Megabyte and Bob. (Null Bot of the Bride)
At the time of the wedding, Cecil had been fitted with a special zip board that connected directly to his upper pole. This one was also colored the same as his upper bar.
- Cecil's voice was played by Michael Donovan. He also played the voices of Phong, Mike the TV, and Al.
- Cecil's main body is similar to old Compact Macintosh computers right down to the rainbow icon.
- Although several Game Cubes have landed on Dot's Diner, Cecil has never been seen in a Game.
- Cecil was named after a pure object-oriented programming language developed by Craig Chambers at the University of Washington in 1992.
- It is to be noted that Dot stops pronouncing Cecil's name properly from Identity Crisis, Part 1 onwards.
- Not counting unnamed binomes, Cecil is the only character to appear in the series opener, but not the series finale.