These are just the characters I felt like putting together bios for (may or may not put more here eventually), and is nowhere close to all of C.O.G.'s current and former personnel, and for that I direct you to their own personnel page!
CURRENT & FORMER C.O.G. STAFF
Dr. Milo T. Pinkerton III (1996 - Present)
Is the C.O.G.'s simultaneously-ridiculously-smart-but-also-kind-of-unwise leader. He boasts an I.Q. of 300, and is what you may expect from a typical "mad scientist": Brilliant, but arrogant, vain, mean, and with total disregard for the life of others, rather seeing them as mere test subjects to be tinkered with and tossed aside.
As he and the other C.O.G. personnel are from Dimension M, or the musical dimension, music permeates all of Pinkerton's potential plans or ideas. He understands the difference between the musical and non-musical dimensions and uses this to his advantage, perceiving the C.O.G.'s "concerts" rather as scientific lectures to educate the masses.
Dr. Z (2001 - Present) AKA Dr. Zaemon Abdul Siddartha Mohammad Achmell Tutmos Abram Ali Hermes Odin Mahatma Dahali Martin Luther Hussein Kali Rocka Babu Haegiegi III
Is the C.O.G.'s own funky-fresh middle-eastern man from "Iwanachickistan" who takes care of the religious side of world domination (and bass!). Dr. Z believes himself to be The Chosen One, and that he will eventually be promoted to full godhood once his cult has grown large enough.
His turban is adorned with a gem that has mystical powers, amplifying Dr. Z's charisma to godlike levels. However, it only works on non-musical people. Anyone who is more musically inclined will see right through this schtick and probably laugh at him.
Dr. Z is particularly interested in growing his harem of women, but sometimes he may charm men into his cult. (Which he has no interest in. But, hey, more people!)
Drumbot (1996 - Present)
The robotic creation of the original C.O.G., Drumbot was created to handle percussion and menial lab cleaning by Dr. Procyon and Dr. Pinkerton, just before the C.O.G.'s first lecture. Drumbot is quite overbuilt for his tasks, having a sophisticated electronic/organic/animated brain, self-improving artificial intelligence and self awareness. This has given it quite an attitude.
As a cartoon creature, Drumbot is at the mercy of the Secret Lab's Dimensional Stabilizers to keep it from melting into ink and paint. Drumbot has all the powers of an animated cartoon character, chief among these being that he simply cannot be killed.
Filbert W. Snodgrass (1997 - 2000, 2021 - Present)
Junior Scientist In Training
Filbert is an unfortunate assistant to the C.O.G., accidentally causing more trouble than help from loitering around the lab and pressing just about everything you shouldn't. Expelled from every science institution for his ineptitude, he developed an interest in "Extreme Science" and began to idolize the C.O.G.. Eventually, Filbert wore Pinkerton down enough that he reluctantly let him into the C.O.G. as a Junior Scientist In Training.
Filbert is a total fool (So much that his chronic clumsiness once caused him to accidentally destroy a planet with millions of innocent inhabitants!), geek, and a "girly-man" according to one account. He's the only current member of the C.O.G. who believes himself to be "Good". Like that'll get him anywhere!
Dr. Harry A. Rachnid (2005 - 2010)
The C.O.G.'s necromancer and total creep, Rachnid was originally a demigod, related to Arachne and Cronus, before being deposed to the mortal realm!
For the first time in a millenium, Rachnid finds himself part of a group -- The C.O.G., who are his only allies, rather than the family that rejected him. He's DEFINITELY a wizard of some kind and NOT a scientist, but Pinkerton refuses to believe this fact.
Rachnid is in charge of reviving Pinkerton's body whenever he dies, typically by his own inventions (Rachnid has a deal with the Angel of Death, so this cheating death is permitted.). Other C.O.G. personnel believe these revivals to be through cloning, rather than magic, but Rachnid makes no attempt to correct them on this and instead prefers to keep the details of his powers under wraps.
Dr. A. Pentatonic (1999 - 2004)
The C.O.G.'s habitually-inebriated guitarist and scientist of questionable qualifications, Pentatonic slouched around the lab for years 'til an unfortunate encounter with "Darth Inscrutable" and the Time Door left him stranded in the future!
Also, he and Pinkerton ran over Dr. Z's dog.
"Dr. A. Pentatonic" (Antonioni Pentatonicci) (1998 - 2000)
From the mean streets of Brooklyn, Antonioni Pentatonicci first met up with the C.O.G. at a lecture in a seedy laboratory on the lower east side. Having disposed of the REAL Dr. A. Pentatonic early in 1999, Pentatonicci spent the next two years attempting to weasel his way into the C.O.G. by impersonating the real Penatonic with the aim of someday deposing Pinkerton and installing the mob's top boss as leader.
He does play a mean guitar! (And has a very-impressive very-illegally-obtained guitar collection.)
Dr. Procyon Lotor (1996 - Present)
One of the original founding members of the C.O.G., most C.O.G. personnel are either flesh & blood or metal & plastic, but Dr. Procyon is ink & paint! In 1999, after a mishap testing a nodal energy point, Dr. Procyon was sucked into Dimension C and was transformed into a cartoon raccoon! Though she seems pretty content in Dimension C and still keeps in touch with the C.O.G. from there.
Dr. Procyon is both the father and mother of Drumbot! Drumbot is also a living cartoon, and makes use of a Dimensional Stabiliser to keep itself from melting into ink and paint.
Prof. Milo R. Pinkerton I
Millionaire, philanthropist, inventor, and Pinkerton III's grandfather... Though he doesn't like that last one. By the early decades of the 20th Century, Prof. Milo R. Pinkerton I had amassed a small army of cutthroats, mercenaries, and musicians and, by 1920, had not only established his reputation as a musical mad scientist & world class jazz crooner, but had also made serious inroads into actual World Conquest!
Pinkerton I is still alive today (Despite being born well over 100 years ago! Time travel is weird, y'know.) and actively resents his grandson's continued inability to achieve his evil ends...
Pinkerton I has his own band, The New Orleans Steamcog Orchestra!