Wander (Jack McBrayer) is the main character of the whole franchise. He travels planet to planet with his best friend, Sylvia helping people have fun and live free, all against Lord Hater and his army of Watchdogs. His purpose in life is to help those who need help.
Lord Hater (Keith Ferguson) is the main antagonist of the franchise. He wants to conquer planets and destroy Wander (and Sylvia) at the same time. He is a whiny, selfish, insecure, jerk. He has his own army of Watchdogs led by his #1 henchman, Commander Peepers.
The Watchdogs (Sam Riegel, Tom Kenny, Keith Ferguson, Various Others) are Lord Hater's army, the make up the entire bulk of the army. They all have eyeballs for heads and is unknown how they are able to talk.
Lord Dominator (Fred Tatasciore) will be Lord Hater's rival as the "Greatest in the Galaxy" in the Second Season.  His silhouette was first seen in the Season 2 poster and later in "The Rider" animatic laughing maniacally.
Emperor Awesome (Sam Riegel) is a cool, cocky, anthropomorphic shark who is one of Lord Hater's greatest rivals, one time the battled for control of the entire universe. He also has a crush on Sylvia and always flirts with her whenever he can as of "The Fancy Party".
The Fist Fighters are Emperor Awesome's army. They can be considered the opposites of the Watchdogs as they have hands for heads instead of eyes. So far, they have only appeared in "The Picnic" and "The Party Animal", and they came back in "The Gift".
Doom Dragon (Fred Tatasciore) is a dragon that first appeared in "The Egg". Wander thought it was a mother off a baby and forced Sylvia to go on a quest and bring it back to her. But it turns out it was the wrong baby. It later reappeared in "The Brainstorm", when Lord Hater and Peepers were brainstorming plans to take over. Flendar and Peepers revealed they were called "Doom Dragons", during the thought of using Doom Dragons. It later made a cameo appearance in "The Epic Quest of Unfathomable Difficulty!!!"
Sir Brad Starlight (voiced by James Marsden) is a character who first appeared in "The Hero" to help Wander and Sylvia save a princess, but it turns out he's a delusional, whiny man-child who just kidnapped the princess for himself in order to fulfill "The Prophecy" which is his diary, he returned in an episode called "The Enemies" and teamed up with Lord Hater.
Captain Tim (Fred Tatasciore) is an alien-pet type creature that first appeared in "The Pet". Wander rescued him from a ship that blew up. He is currently living with Lord Hater and is driving the Watchdogs insane. He later makes a cameo appearance in "The Little Guy". He is confirmed to come back (Most likely in the show's second season).
Prince Cashmere (Bill Fagerbakke) is bravest prince of "Baaaaa-halla", and the leader of his strong army of goat warriors. He first appeared in "The Troll", where Wander and Sylvia helped him take down an obnoxious troll.
Lord of Illumination (John Hodgman) is an alien who appeared in The Box. He has four friends who are also Lords of Illumination. He initially gave the box to Wander and Sylvia as a test of unknown nature, which they passed. However Wander, wanting to know what was inside the box, counted various things as Sylvia realized the truth and demanded that the Lord of Illumination put something in the box. He initially declined, but when Sylvia angrily showed him she was serious and he, along with the other Lords of Illumination, put a few items in the box. With Wander now back to normal he and Sylvia left, the Lord of Illumination trying to give a lesson before being shut up by Sylvia. He returned in a 11-minute Christmas entitled "The Gift".
Westley (Aziz Ansari) was formerly the littlest Watchdog cadet in Hater's army until he befriended Wander and Sylvia near the end of the episode. He is also the first Watchdog to have his name revealed. He first appeared in "The Little Guy".
Moose (voiced by no-one, as he has not spoken in the series yet) is the biggest and most muscular Watchdog on the team. Along with Westley, he first appeared in "The Little Guy".
Beeza (Tara Strong) is the leader of the species whose planet keeps getting destroyed by Buster the giant dog. However, Wander was able to find her and her group a forever home, which is Buster. She also first appeared in "The Ball" as of now her last appearance is "The Gift".
The Potted Plant (voiced by unknown) is a plant bounty hunter who can actually eat you up. It's fate was being killed by Peepers in an attempt to capture Wander and Sylvia. But he somehow returned in "The Gift".
Princess Demurra (voiced by Jennifer Hale) is the princess from "The Hero" Wander, Sylvia, and Brad Starlight were out to rescue, but Brad just did for "The Prophecy", and kidnapped her, Wander, Sylvia, King Draykor, and the Hogs were going to rescue her but it turns out she handled it herself and tied him up.
King Draykor (voiced by Fred Tatasciore) is the "evil" dragon king that "kidnapped" Princess Demurra and "stole" her to his "Labyrinth of Delusion", it turns out he was a good guy while Starlight was the bad guy.
Harvax (voiced by Jeff Bennett) is a dark blue steed like alien who first appeared in "The Time Bomb", him and Stok were racing against Wander and Sylvia, and they constantly teased Sylvia by calling her "Time Bomb", at the end, they won the race but were disqualified since Harvax was using a fake proboscis, therefore, Wander and Sylvia were the real winners of the race.
Stok (voiced by Charlie Adler) is a yellow Woodstock bird whose best friend is Harvax, all he can say is "Tick-tock" and "boom", at the end, they won the race but were disqualified sine Harvax using fake proboscis, therefore, Wander and Sylvia were the real winners of the race.
Trudi Traveler (voiced by Edie McClurg) is an elderly tourist who challenged Wander to see different planets in the galaxy as a contest/competition, it looks like she may have won, but at the end of the episode, it was revealed that she used clones to help her, proving that Wander actually did win.
Planet Janet (voiced by Kari Wahlgren) is a planet who first appeared in "The Lonely Planet", at first wanted to keep Wander all to herself, but then learned that you can't keep everything forever, she eventually fell in love with Maurice, a moon with a mustache.
Maurice (Rene Auberjonois) is a moon with a mustache who is currently in a relationship with Janet.
Bob (voiced by Tom Kenny) is the 4th named Watchdog. He first appeared in "The Brainstorm".
Huckleberry Knucklehead (voiced by Owen Faust) is a giant toddler who first appeared in "The Toddler", Wander found him wandering around by himself, and throughout that episode, Wander and Sylvia were trying to get the baby to its parents, at the end of the episode, they did, but they're real tiny fleas.
Queen Entozoa (voiced by Rich Fulcher) is an alien queen who appeared in "The Fancy Party", she invited all the villains to her place (including Wander and Sylvia since Wander is "the most wanted fugitive in the galaxy"), she is 1,000 years old. At the end of the episode, it was revealed that a slug demon was possessing her body for all those years, it was going to take over Lord Hater's body, but then Wander did the Heimlich to save him, so now, the queen is now a sandwich, and now wants revenge on Wander, Lord Hater, Sylvia, and Peepers.
Destructor (voiced by Fred Tatasciore) was the main antagonist of the episode "The Epic Quest of Unfathomable Difficulty!!!", apparently, his father threw away his sock when he was young so he was evil until Wander and Sylvia returned the sock back to him.
Teddy (Tom Kenny) is the 5th named Watchdog. He first appeared in "The Gift 2: The Giftening", his mission was to capture Wander and stop him from giving gifts but he got infected with happiness. His goal was to find a girl he met on Shore Leaf, buy her a ring, and ask her to be his.
Pete (Fred Tatasciore) is the 6th named Watchdog. Along with Teddy, he first appeared in "The Gift 2: The Giftening", he worked with Teddy to try and capture Wander. But like Teddy, he got infected with happiness. His dream was to dance.
Thrax (voiced by Fred Tatasciore) is a purple robotic-alien like creature who first appeared in "The Buddies". He was thrown in Hater's Prison Dimension and befriend Wander sometime before that happened. He hates Lord Hater as he's the one who threw Thrax down there in the first place.
Little Bits (voiced by G. Hannelius) is purple kitten who first appeared in "The Stray". She was a bounty hunter hired to capture Wander (and Sylvia). However, by the end of the episode, Sylvia got her and Wander free and Little Bits almost got dipped into boiling oil by Lord Hater until she used her cuteness on him.
The Insurgent Generals are a team that first appeared in "The Big Job":
General Outrage (voiced by Steve Blum) is the founder of the team, he gets angry a lot which explains his name. Like he got mad because when Wander and Sylvia were on the team, Wander's job was to guard the door but he let many people in which made him mad.
Mooplexian (voiced by Fred Tatasciore) is a highly-advanced species that also first appeared in "The Funk". Lord Hater and Peepers thought Mooplexian and his other minions were stupid until Mooplexian took Hater and Peepers inside his mind to show them that they're smarter than Hater and Peepers thought they were.
Ryder (voiced by Will Arnett) is Sylvia's former partner, he first appeared in "The Rider".
Barry is the 8th named Watchdog who also first appeared in "The Rider". Apparently, it was his 30th birthday in that episode and Wander made it his goal to celebrate Barry's birthday. He eventually did, near the end of the episode, he called Barry's name, wished him a happy birthday, and threw him a birthday cake. Ceasing the capture as the Watchdogs also wished him a happy birthday.
Tim (Fred Tatasciore) is the 9th named Watchdog. He made his first appearance in "The Gift", looking for the conference room that Hater and Peepers were in. Wander told him it was in Conference Room 1-A. But he didn't know it was him so he called him a "mysterious voice" and threatened to blast him to into bits but then Wander threw out a present and then he became Happy. He is the last named Watchdog of Season 1 and overall the last named character of Season 1.
This page uses content from the English Wikipedia. The article or pieces of the original article was at Wander Over Yonder. The list of authors can be seen in the page history. As with Disney Wiki, the text of Wikipedia is available under the GNU Free Documentation License.