Who is the swamper in "Of Mice and Men"?

Candy is the "old swamper" in John Steinbeck's novella Of Mice and Men. The term "swamper" simply refers to the fact that he literally "swamps" or washes out the bunkhouse where the men on the ranch live. When we first meet Candy in chapter two, he is carrying a broom in his left hand because he lost his right hand in a work related accident. Steinbeck describes him,

The door opened and a tall, stoop-shouldered old man came in. He was dressed in blue jeans and he carried a big push-broom in his left hand. 

He's followed around by a "a drag footed sheepdog" with "pale, blind old eyes." He seems happy enough in the beginning and is used by Steinbeck to describe the various characters on the ranch, including the Boss, Slim, Crooks, Curley and Curley's wife.

At the end of chapter two, however, Candy's life takes a depressing turn as Carlson, a "powerful, big stomached" worker on the ranch suggests to Slim that Candy's dog is too old and decrepit and should be put out of its misery. He wants Slim to give Candy one of his puppies (one of them is given to Lennie). Slim, being the de facto leader of the men approves Carlson's idea, and in chapter three Carlson shoots Candy's dog.

The old swamper becomes despondent over the loss of his dog until George begins to describe the "little piece of land" he and Lennie hope to one day have. Because Candy received a settlement from the ranch over the loss of his hand he has $350 which he can contribute. He tells George:

“S’pose I went in with you guys. Tha’s three hunderd an’ fifty bucks I’d put in. I ain’t much good, but I could cook and tend the chickens and hoe the garden some. How’d that be?” 

George agrees and the "thing they had never really believed in was coming true." Candy also serves to provide foreshadowing for the ending of the book as he tells George,

“I ought to of shot that dog myself, George. I shouldn’t ought to of let no stranger shoot my dog.”

Rather than let Curley or one of the other men kill Lennie, George takes Carlson's gun and shoots his friend in the back of the head. With the dream gone, Candy expresses his bitterness over the loss his future as he stands over Curley's wife,

“You done it, di’n’t you? I s’pose you’re glad. Ever’body knowed you’d mess things up. You wasn’t no good. You ain’t no good now, you lousy tart.” He sniveled, and his voice shook. “I could of hoed in the garden and washed dishes for them guys.”