The Life of SpongeBob SquarePants/Universe/Characters

Main:

 * SpongeBob SquarePants, protagonist of the series, extremely-skilled fry cook at the Krusty Krab
 * Patrick Star, deuteragonist of the series, SpongeBob's dim-witted yet fiercely loyal best friend
 * Squidward Tentacles, tritagonist of the series, despises SpongeBob, Patrick, and Mr. Krabs most of the time and desires to get out of his job as Krusty Krab cashier, but will do anything to get them out of grave danger
 * Eugene H. Krabs, owner and operator of the Krusty Krab, employer of SpongeBob and Squidward, shrewd and very capable businessman who brought the Krusty Krab to glory, but also extremely greedy, unscrupulous, and manipulative
 * Sheldon J. Plankton, owner and operator of the unsuccessful restaurant Chum Bucket, archnemesis of Eugene H. Krabs
 * Sandy Cheeks, friendly, intelligent squirrel, close friend of SpongeBob and Patrick
 * Gary the Snail, SpongeBob's loyal pet snail

Recurring

 * Karen Plankton, wife of Sheldon J. Plankton, with whom she has an unstable, love-hate relationship. Sometimes complicit in her husband's evil activities, at other times fiercely and cynically critical, if not entirely indifferent

Major background:

 * Fred, brown fish, married to Sadie Rechid, Bikini Bottom citizen
 * Sadie Rechid, orange and tan fish, married to Fred, Bikini Bottom citizen
 * Nat Peterson, yellow tan fish with a purple fin, Bikini Bottom citizen
 * Harold "Bill" Reginald, blue fish with white shirt and red Speedo, Bikini Bottom citizen
 * Old Man Jenkins, elderly Bikini Bottom citizen, skinny with gray skin
 * Nancy Suzy Fish, gray white-haired fish, Bikini Bottom citizen
 * Debbie Rechid, pink fish, Bikini Bottom citizen
 * Sheldon (fish), gray fish with a purple fin, Bikini Bottom citizen
 * Sheila, gray white-haired fish, Bikini Bottom citizen
 * Bill, grayish-brown fish, Bikini Bottom citizen

Other/lesser characters:

 * Gustav Savalas, blue shark, doctor at the Bikini Bottom General Hospital, zealous defender of the hospital's policies
 * Thomas Reywal, Bikini Bottom lawyer
 * Joseph SquarePants, Bikini Bottom lawyer, cousin of SpongeBob
 * Ari Goodfish, judge at the Bikini Bottom Courthouse
 * Thomasino Ramshackle, notorious leader of bandits based in the wreck of the USS Saratoga
 * Ribert Ramshackle, bandit, son of Thomasino