These are the characters from the somewhat popular BZP comedy It's a Mad House!. Over its two year run since it debuted August 28, 2010, it has acquired multiple characters.
Regular characters are characters who tend to appear in most chapters, although not always. Some were brought in later on, and if they weren't brought in at the beginning of Season One, that means they weren't technically a regular until Season Two.
Recurring characters are characters who may be very important to the story, but don't show up all the time. All villians are like this.
Classifications are races, species, general characters, that show up alot, but are never the same (well, sometimes).
Kazarac: Kaza is the leader of the Toa Cerun, which he remembered towards the end of Season Two. Before he transformed into a Toa, he used a Toa Simulation Suit (TSS) which gave him minor control over multiple elements. Now he only controls Ice and Electricity, but is more powerful with them. His legendary weapon is the Phoenix Blade, which helps the user glide and jump farther (though not straight-up fly), as well as having fire powers.
Brekit: The Toa Cerun of Air, he originally was being forced to work by Kurahkzon (going by the alias Warrior), but that was only to ensure that he would not remember being a Toa Cerun. Towards the end of Season Two, though, four of them remembered, included him.
Nuhrii: Originally sent as an assassin to kill Kaza, he later allied with him temporarily, only to discover that he is a Toa Cerun, the Toa Cerun of Sugar.
Narra: Formerly the Narrator, it turns out he was appointed that position to help jog his memory. He is actually Narra, the Toa Cerun of Fire.
Iruini: A goofy but intelligent amateur scientist, he turned a downstairs room into a lab along with Norik, where he invents multiple things that prove to be helpful. Somehow. Usually.
Norik: Norik is a Turaga who was mistakenly given the energy of a Toa, who goes insane when he consumes sugar and is Iruini's scientific partner.
Vezon: The insane Bionicle who usually causes mischief and other stuff. He does whatever he wants, but sometimes helps out-usually accidentally.
Zaktan: The Piraka who is somewhat normal, helps, and has a crush on Hahli. Vezok is his wingman.
Vezok: The Piraka who is best friends with Zaktan, is his wingman, and is unfortunately Vezon's twin, somewhat faternal.
Makuta: Makuta is not evil, actually, and is normal, helpful, and has a unique style of scheming. Don't toss him in with Pridak or Vezon, now.
Hydraxon: Hydraxon is a normal, heroic Bionicle who likes hanging out with the others and helping Kaza.
Pridak: The leader of the Barraki special ops team, he commands them fearlessly, leading them on many adventurous and insane missions.
Takadox: Following in the footsteps of Pridak, he is the commander when Pridak is not around and is also the brains of the operation.
Ehlek: Ehlek is the team's ranged specialist, also following in Pridak's footsteps.
Carapar: With varying intelligence levels, he is the brawn and battering ram.
Mantax: He is the melee specialist, often ambushing his foes for a good 'ol swordfight.
Hahli: The Toa Inika that Zaktan has a crush on, she is the only female so far and thinks of most of the others as idiots.
Lewa Nuva '08: Lewa was bought by Vezon for an experiment involving a buttery teleporter. He is not insane.
Tahu: The conceited Bionicle who used to work for the Great Beings, before being fired. Kaza took him in.
Kurahkzon: Kurahkzon is an evil being who seeks to destroy Kaza and may have some connection to his past.
Lehrahk: The green Rahkshi who escaped from Kurahkzon's wrath and teamed up with the evil Barraki.
Kalmah: The leader of the evil Barraki, only he and Lehrahk have turned up after the other evil Barraki were flushed by the good Barraki.
Drarak: The Great Being of Intelligence, he likes Kaza and is the closest Great Being to him.
Dinys: The Great Being of Strength, he has also taken a liking to Kaza and is second closest to him.
Stallak: The Great Being of Ignition, he originally liked Kaza, although once he got to know him he began to hold a grudge...perhaps he remembered something...
Sehrah: The evil Great Being of War, he holds a grudge against Kaza, who stopped him from taking over the City of the Great Beings after first obtaining his powers.
Evil Barraki: They worked for Kalmah, but haven't been seen since the good Barraki flushed them in the Cincinatti Zoo.
Urohk: Urohk are generally black-armored and strong beings who work for Kurahkzon as members of SOAP. They don't have any known elemental powers.