This is a list of all Climbing Torches characters in approximate order from their first appearance. I will update this when more is learned about these characters. Be warned: There are spoilers.
Top Hat Guy is a high-ranking servant of the Shadowy Figure, and originates from xkcd (which is not very kid-friendly). He helped capture the Universe Globe and, at one point, was sent to jail in 1930, and immediately escaped. He then captured the main characters, but was defeated by Bill Nye. It was then revealed that he was a spy for a group called the Collectors.
The Shadowy Figure
The Shadowy Figure is a millennia-old being of immense power, who led an army to capture the Universe Globe. He then followed the Main Characters around, teleporting them to different worlds.
Epyk is a Rocknutist paladin who actually laid the final blow on the devil Mizgomuth. She tried to convince Varis to give up the One Fidget to Rule them All. She then regrouped with the party in 1930, and was captured in Azeroth.
Aaron is a cleric of Rocknut, God of Plants and Environmental Protection. He fought the devil Mizgomuth along with Epyk Skyrocket, Masterous, and Varis Darkwood. They then fought Kanjar Ro. He then ended up in the world of Destiny, then later in 1930, then was captured in Azeroth.
Masterous is a wizard. He fought Mizgomuth and helped stop Kanjar Ro. He helped destroy the One Fidget. He then regrouped with the party in 1930, and was captured in Azeroth.