Set in a town known as Shadow Falls, after being bitten by a strange wolf, a young adult turns into a werewolf at night and ends up dealing with various threats.
- Jeffrey Morrison/Howler (voiced by Charlie Schlatter in his human form and Kevin Michael Richardson in his werewolf form) - a shy and well-meaning young adult who can turn into a werewolf at full moon, being out to revert his state while he fights threats whenever he has to.
- Bella Stoker (voiced by Jennifer Hale) - a generally kind vampire who is Howler's love interest, often aiding him.
- The Ghost Twins, consisting of:
- Frank N. Stein (voiced by John DiMaggio) - a Frankenstein monster who is unintelligent. Despite that, however, he gets random bursts of intelligence. It is later explained by Bella Stoker that he has "multi-intelligence disorder", making him smart at times and stupid at other times.
- Greg (voiced by Doug Lawrence) - a gargoyle who is immature and is usually a narcissist.
- Lex the Lynx (vocal effects by Dee Bradley Baker) - a dimwitted lynx who acts like a cat and loves to play. He was rescued by George when a grizzly bear tried to eat him once.
- Wylda (voiced by Kimberly Brooks) - a witch who likes making potions and casting spells, either helping or harming someone. However, whenever her potions/spells harm someone, it's usually unintentional.
- The Zombie Duo, consisting of:
- Mayor Vlad Dracula (voiced by Clancy Brown) - a vampire who is the mayor of the forest all of the supernatural creatures in Shadow Falls live.
- Liz the Lizard (vocal effects by Frank Welker) - a lizard who became Lex's best friend next to George. She was first introduced in the franchise in Collin and Howler: Speedin' and Howlin'.
- Phillip (voiced by Bumper Robinson) - a fun-loving young adult who is one of Howler's friends he hangs out with whenever it's daytime and he's not hanging out with his supernatural friends. However, he and Lacey end up finding out Howler's secret in Howler 3.
- Lacey (voiced by Mae Whitman) - a studious young adult who is also one of Howler's friends he hangs out with. Just like with Phillip, it's usually whenever it's daytime and Howler's not hanging out with his supernatural friends. However, she and Phillip end up finding out Howler's secret in Howler 3.
- Boris Morrison (voiced by Fred Tatasciore) - Jeffrey's strange father who has a high interest in the supernatural.
- Lisa Morrison (voiced by Susanne Blakeslee) - Jeffery's mother who is really caring and protective of Jeffrey/Howler.
- Kris and Kloe (voiced by Ashley Johnson and Lacey Chabert, respectively) - two twin kitsunes who both have a crush on Howler, despite him dating Bella.
- Jacky (voiced by Tim Curry) - a fictional evil clown character who is from George's favorite show, The Clown & Dinosaur Show.
- Rex (voiced by Charlie Adler) - a fictional Tyrannosaurus rex character who is Jacky's partner crime.
- Akamai (voiced by Kate Higgins) - a beautiful Hulu girl who Greg falls in love with.
- Sasha (voiced by Alanna Ubach) - a succubus who was an antagonist in Howler 6, but redeemed when she gets betrayed by the General.
- Gwen (voiced by Kath Soucie) - a ghost woman who is the Ghost Twins' mother, being pretty beautiful and very caring of her children.
- Ophelia (also voiced by Ashley Johnson) - a vampire who is rather naive about the world around her.
Introduced in spin-offs
- Roy Whitney (voiced by Josh Keaton) - a man who is a conspiracy theorist as he helps Jeanette to find Desire.
- Jeanette Helsing (voiced by Vanessa Marshall) - a woman who wants to eradicate all supernatural beings, whether they're good or bad.
- The Naga (voiced by Richard Steven Horvitz) - a giant snake with humanoid arms who constantly tries to kidnap Howler and/or his friends, but always fails miserably. He is basically a recurring character.
- The Black Knight (voiced by Greg Eagles) - a ghostly knight figure who tries to take over the Shadow Falls forest.
- The Headless Horseman (voiced by Crispin Freeman) - a headless horseman who wants to scare people.
- Mr. Impton (voiced by John Kassir) - a greedy Imp who loves to steal stuff for fun.
- Gold Statue (voiced by Catherine Taber) - a golden living human statue who guards a cave.
- The Nightstalker (voiced by Keith David) - a demonic entity who is out to conquer Shadow Falls.
- Shadow Howler (voiced by Robin Atkin Downes) - a shadow werewolf that is an evil version of Jeffrey/Howler created by the Nightstalker.
- The Cockatrice (vocal effects by Frank Welker) - a two-legged dragon monster with a rooster's head.
- Baba Yaga (voiced by Tress MacNeille) - an ugly-looking woman who uses a pestle.
- Chimera (voiced by voiced by Rob Paulsen (lion), Charlie Adler (goat), and Maurice LaMarche (snake)) - a lion-goat-snake hybrid.
- Medusa (also voiced by Susanne Blakeslee) - a female human creature called a Gorgon with snakes for her hair that can turn anyone who looks at her into stone.
- Mau Taioo (voiced by Jim Cummings) - a Hawaiian cult leader who aims to rule over Hawaii.
- Leilani (voiced by Colleen Villard) - a member of the cult who is Mau's second-in-command.
- Kaupe (voiced by Patrick Seitz) - a malicious spirit that lures people to their death.
- Naggette (voiced by Jill Talley) - Naga's grouchy mother.
- Shade (voiced by Ron Perlman) - an entity of darkness who was responsible for spreading the virus.
- Desire (voiced by Grey Griffin) - a spirit-like humanoid who is responsible for killing off Jeanette's parents back when she was a little girl.
- The Cthulhu (voiced by Michael Dorn) - a giant octopus-human-dragon hybrid who aims on enslaving mankind.
- Angelica, Sergei and Buddy (voiced by Kari Wahlgren, Rob Paulsen, and Charlie Adler, respectively) - a trio of imps who love to cause chaos.
- Dagon (voiced by Dave Boat) - a reptile-like humanoid entity who TBD.
- Mi-Go (voiced by Kirk Thornton) - a crustacean-like entity who TBD.
- Shub-Niggurath (voiced by TBD) - an TBD entity who TBD.
- Nyarlathotep (voiced by Dave B. Mitchell) - TBD
- The General (voiced by Chris Williams) - a corrupt ghoul general who wants to start a war.
- Skull Banshee (voiced by Vanessa Williams) - a skeleton/banshee hybird.
- Razor (voiced by Christopher Judge) - a monstrous wolf/vampire hybrid.
- Doctor Dream (voiced by Steven Blum) - a strange entity who trapped Howler and his friends in Dream Land.
- The Cloud Colossus (voiced by Tim Blaney) - a giant cloud-like creature.
- Mona, Lisa and Joan (voiced by Rachael MacFarlane, Stephanie Sheh, and Cindy Robinson, respectively) - three Dullahans who act like cheerleaders.
- Golden Clown (voiced by Mark Hamill) - an evil clown who wears golden clothes.
- Fire Starter (voiced by TBD) - a fire being who causes large fires.
- Brain Crusher (voiced by David Kaye) - a giant brain-like being who attempts to steal other brains and crush them.
- Lady of the Mirror (voiced by Erica Lindbeck) - a feminine figure who is able to get inside mirrors and pop out of them to grab her figures.
- King Cuviper (vocal effects by Frank Welker) - a cucumber-like snake creature.
- King Lycan (voiced by Terrence C. Carson) - a werewolf who claims himself as king of the werewolves.
Introduced in spin-offs
- The Owlman (vocal effects by Frank Welker) - an owl-like humanoid.
- Howler (2007)
- Howler 2: The Nightstalker (2009)
- Howler 3: Lost in Hawaii (2011)
- Howler 4: The Dark Virus (2015)
- Howler 5: Night of the Cthulhu (2017)
- Howler 6: The Great War (2019)
- Howler 7: Stuck in Dream Land (2020)
- Howler 8: Rise of the Werewolf King (2021)
- Howler: Ultimate Werewolf (2018-present)
See Howler (2019).
Direct-to-video film adaptions
See Howler (2019).
Comic book adaption
See Howler (2012-present).
- Lex's Origins (2018)
- TBD (2020)
According to the "Howler 10th Anniversary" press release, more spin-offs are potential. On DeviantArt on October 25th, 2019, when asked about more origin stories focusing on other major characters, he replied that he expressed interest in doing so. This ended up being confirmed on October 31st.
See Howler and Charlotte: Supernatural Combination (2019).
The franchise received very positive reviews, with fans praising it for its humor, writing, and animation.
- Bella's name is a pun on the names of the actor, Bela Lugosi, and the writer, Bram Stoker.
- According to Daniel in an interview, Howler started off as a short comic he made back in 1992 when he was in high school to impress his friends, as it was about a werewolf and a vampire (whose names were Wayne and Vicky) capturing humans, only to fail miserably at the end.
- Fans believed that the characters, Georgia and Lex, were inspired by Rachael and Bulk from Daniel Wright's previous work, Me and a Different Dimension.
- In Howler 3: Lost in Hawaii, it is confirmed that Shadow Falls is located in Massachusetts.
- Throughout the series, starting in Howler 2, the wolf that bit Jeffrey has been making cameos.