Cheddar

Context
Cheddar was a stray dog who was adopted by Mr Cheese, But soon after, they parted ways so Cheddar could pursue his own dreams.

Personality
Personality-wise Cheddar is very loyal to Mr Cheese and will help him when necessary.

Mr. Cheese
Cheddar and Mr. Cheese have become very good friends ever since Cheddar saved him from dying in an alleyway.

TheGentleman
Cheddar enjoyed playing with him because TheGentleman was a friend of Mr. Cheese.

Player
Despite Cheddar biting Player he probably doesn't hate him and was just following orders from Mr. Cheese.

Doctor
He's presumably happy that he fixed up Mr. Cheese, but was mad at him when he called him a soft Gruyère.

Captain
Despite Cheddar biting Player and Captain being a friend of Player, he might also as well not too much like Captain.

Mr Mean Cook
Cheddar doesn't like Mr Mean Cook because he kicked him out of his restaurant, after finding Cheddar eating the food in the kitchen.

Toto
He probably wouldn't be too happy with Toto if he found out he replaced him.

The Children
Cheddar doesn't like the children because they beat up Mr Cheese.

Who Is Mr Cheese?
In the Song "Who Is Mr Cheese?" he is seen running in a field with Mr. Cheese.

Among Us Logic 17
In Among Us Logic 17, Cheddar appears in Mr. Cheese's flashback that he tells to Captain and Player and also bites Player's leg, preventing him from resetting the Seismic Stabilizers on Planet Polus.

Like Father, Like Son
There is a toy of Cheddar on the child’s shelf.

Crewmate's License
He is with Mr. Cheese when TheGentleman says he misses his cheesy friend.

The Death of Mr. Cheese
Cheddar was next to Captain and was so sad that Mr. Cheese was dead.

Among us logic: Jailbreak
He is shown to be in the episode in the third sneak peak called "the good stuff"

Trivia

 * Cheddar is Mr. Cheese's pet dog.
 * Cheddar is the fourth pet to appear in the Among Us Logic Series, with the first being Timmy and Franklin, the second being Toto and the third being Not Orange's Mini Crewmate.
 * Cheddar, along with Blue, are the only two characters to appear in a Music Video before being added to the Among Us Logic Series.
 * Cheddar's design is supposed to be that of Mr. Cheese, but if he was a dog.
 * Cheddar is seen in a basketball uniform in Mr Cheese's flashback where he won the Basketball Match for his owner's team.
 * Cheddar counts as a GameToons character even though he appeared in a song before he appeared in a Logic.
 * Cheddar playing basketball is a reference to Air Buds, as Mr. Cheese says “That was a real Air Bud moment!”
 * In Among Us Logic: Jailbreak his name is Lieutenant which is a reference to the military rank Lieutenant