Mark: Time Janitor (James TheLogoMan Version)

Main

 * /Mark Thomas/ (voiced by Rainn Wilson) - a greedy time-traveling janitor who was somehow assigned by the TFBI to travel through time to fix historical problems, even if he starts some of them thanks to his general ignorance of time-travelling rules and general dickish behavior.
 * Time Pack (voiced by Corey Burton) - a helpful robotic backpack who is Mark's sidekick, often providing historical information and getting him out of troubles while also being able to summon gadgets.
 * Janice Sumbers (voiced by Grey Griffin) - Mark's ditzy and girly best friend/girlfriend who occasionally aids him to solve some of his problems, even if she ends usually causing mayhem due to her lack of knowledge about time travelling.

Supporting

 * Don Blanc (voiced by Frank Welker) - a tough-as-nails time agent and June's partner who teaches Mark about time travel and history while he tries to keep Mark away from causing chaos.
 * June Bliss (also voiced by Grey Griffin) - a seductive time agent and Don's partner who is in love with him, helping Mark to fix the mistakes he made TBD.
 * The Time Boss (voiced by Patrick Stewart) - the literal head of the Time Federal Bureau of Investigation who is literally just a head on a computer screen and often argues with Mark due to his lack of experience and his constant screw-ups, often giving him a chance to try again.
 * Robo (voiced by Daran Norris) - a robotic assistant to the Time Boss who usually gets TBD.
 * Linda Thomas (voiced by Mae Whitman) - Mark and Janice's TBD daughter in the future who first appears on Lost and helps her father to deal TBD.
 * Time Pack V.8 (voiced by Eric Bauza) - an updated version of Time Pack who TBD.

Historical figures

 * Leonidas (voiced by Thomas F. Wilson) - TBD
 * Queen Cleopatra (voiced by Cree Summer) - TBD
 * Alexander the Great (voiced by S. Scott Bullock) - TBD
 * Joan of Arc (voiced by Nika Futterman) - TBD
 * Leonardo Da Vinci (voiced by Carlos Alazraqui) - an artist from the Renaissance era.
 * Christopher Columbus (voiced by J.K. Simmons) - TBD
 * George Washington (voiced by Maurice LaMarche) - TBD
 * Frederick the Great (also voiced by Corey Burton) - TBD
 * Abraham Lincoln (also voiced by Maurice LaMarche) - TBD
 * Charles Darwin (voiced by David Tennant) - TBD
 * Theodore Roosevelt (also voiced by Daran Norris) - TBD
 * Pierre and Marie Curie (also voiced by J.K. Simmons and Grey Griffin, respectively) - TBD
 * Michael Collins (voiced by Ryan Curcwald) - TBD
 * Frida Kahlo (voiced by Alanna Ubach) - TBD
 * Franklin Roosevelt (voiced by Ed Asner) - TBD
 * Winston Churchill (voiced by Martin Starr) - TBD
 * Charles de Gaulle (also voiced by Maurice LaMarche) - TBD
 * Anne Frank (voiced by Paget Brewster) - TBD
 * Albert Einstein (voiced by Dwight Schultz) - TBD
 * Victoria Woodhull (voiced by Allison Janney) - TBD
 * Queen Elizabeth II (voiced by Kate Micucci) - the Queen of the United Kingdom since 1952 who TBD.
 * Ronald Reagan (voiced by Jim Meskimen) - TBD
 * Bill Clinton (also voiced by French Stewart) - the President of the United States between 1993 and 2001 who TBD.
 * Hillary Clinton (voiced by Tress MacNeille) - Bill's wife and Secretary of State between 2009 and 2013 who TBD.
 * George W. Bush (voiced by Jeff Bennett) - the President of the United States between 2001 and 2009 who first appeared in TBD.
 * Angela Merkel (voiced by Susanne Blakeslee) - the Chancellor of Germany since 2006 who adverts Mark TBD.
 * Barack Obama (voiced by Keith David) - the President of the United States between 2009 and 2007 who first appeared on The Time Eater.
 * Donald Trump (also voiced by Maurice LaMarche) - the President of the United States since 2017 who first appeared on A Tear in Time.

Antagonists

 * Derrick/The Time Switcher (voiced by Diedrich Bader) - a powerful rogue Time Guardian who sucks souls to stay young and tries to rule all timelines.
 * Bella (voiced by Jessica DiCicco) - Derrick's loyal slave who TBD.
 * Sluggy (voiced by Rob Paulsen) - a genetically modified slug creature who TBD.
 * Bruno (voiced by John DiMaggio) - Derrick's muscular henchman who TBD.
 * Imperion the Time Eater (also voiced by Carlos Alazraqui) - an ancient threat through time who plans to eat all of the timeline.
 * Karm (also voiced by Rainn Wilson) - a vile clone of Mark who has white hair and a scar, wanting to replace him to have full access to TBD.
 * Lori (voiced by Ashley Johnson) - a TBD follower of Imperion who is a master of disguise, usually wearing TBD.
 * Pengix (also voiced by Daran Norris) - a penguin-like creature who is known for his rather TBD.
 * Madelyn Judas (voiced by Cassandra Lee Morris) - a TBD time traveller from the same future as Linda who plans on taking over all TBD.

Historical figures

 * Julius Caesar (voiced by Keith Ferguson) - the ruler of the Roman Empire who gains control of modern weapons thanks to Mark and TBD.
 * Attila the Hun (voiced by Fred Tatasciore) - TBD
 * Blackbeard (voiced by Brian Doyle-Murray) - TBD
 * Nostradamus (voiced by Paul Rugg) - TBD
 * Maximilien Robespierre (also voiced by Keith Ferguson) - TBD
 * Napoleon Bonaparte (also voiced by Rob Paulsen) - TBD
 * Jack the Ripper (voiced by Bill Farmer) - TBD
 * Billy the Kid (also voiced by Rob Paulsen) - TBD
 * Jesse and Frank James (voiced by Tom Kenny and also by Jeff Bennett, respectively) - TBD
 * Rasputin (also voiced by Eric Bauza) - TBD
 * Al Capone (voiced by Richard McGonagle) - TBD
 * Bonnie and Clyde (also voiced by Paget Brewster and Fred Tatasciore, respectively) - TBD
 * Adolf Hitler (voiced by Mark Hamill) - the leader of Nazi Germany who is out to conquer Europe and now the entire timeline by stealing a time traveling device and forming a group of Germans and German supporters, being The Birth of Multiple Disasters ' main antagonist.
 * Joseph Goebbels (also voiced by Fred Tatasciore) - TBD
 * Mata Hari (voiced by Stella McDonnell) - a Dutch exotic dancer hired by Hitler to join his army and TBD.
 * Fiedrich Nietzsche (also voiced by Daran Norris) - an infamous nihilist who TBD.
 * Johann Sebastian Bach (also voiced by Mark Hamill) - a German composer who is manipulated into joining his TBD.
 * Joseph Stalin (also voiced by Mark Hamill) - the historical leader of the Soviet Union who is rather anger-prone TBD.
 * Mao Zedong (voiced by Keone Young) - the historical leader of Communist China who gains TBD.
 * Mikhail Gorbachev (also voiced by Keith Ferguson) - TBD