Well I hope you don't mind if I answer this, mind you I only know about the original cartoon series Quintessons ;)
First introduced in the Movie and appeared in various Transformers episodes during Season 3 and were revealed (in the cartoon canon) to be the creators of all the Transformers on Cybertron.
They're basically tentacled beings with energy beams underneath usually seen with 5 faces (with some exceptions in episodes "The Killing Jar", "Dweller in the Depths" and "Madman's Paradise") which were later revealed to be the faces of:
Death (the most common one "We sentence Judge Deliberata to death" FFoD prt 2)
Wrath (Devil, "I praise your decision. Open the pit." FFoD prt 2)
Bitterness (solemn, green and teal face "Indeed, such intuitive powers could present a serious impediment to our operation." FFoD prt 2)
Doubt (pointier green helmet, "Erh, then recovering the journal will be more difficult than we'd imagined." Big Broadcast of 2006)
Laughter (orange seemingly the most benign dude, "It *About the supposed destruction of the Autobots* is a day so long in coming that I am uncertain how to celebrate it." - FFoD prt 3)
Some of their nefarious deeds in the animated series were:
Five Faces of Darkness: Revealed to be the creators of all the Transformers, tricked Galvatron into an alliance with the promise of a fictious Decepticon Matrix, interrogated Kup, Magnus and Spike about Cybertron before sending them to their deaths (they were saved by Arcee, Grimlock, Springer, Rodimus Prime and the Aerialbots) and then nearly destroyed them all by having the Sharkticons (in fact the deranged Galvatron was the one who activated the switch) activating a switch that made all Transformers inert (Spike saved them all)
The Killing Jar: A Quintesson named Inquirata (who is a single faced Quintesson) captured Ultra Magnus, Cyclonus, Marissa Faireborn and Wreck Gar in order to conduct behavoural experiments on them
Dark Awakening: Reviving Optimus Prime as a zombie to lure the Autobots into a trap that nearly succeeded
Madman's Paradise: A rogue Quintesson named Mara-Al-Utha conquered the magical realm of Menonia for millions of years (we are given insight into how the Quintessons dealt with law breakers of their spieces, namely by transporting them into other dimensions)
Forever is a Long Time Coming: Inquirata returns and his plan was to use a time window to kidnap the Autobot leader of the rebellion (that occured over millions of years ago) that drove the Quintessons from Cybertron, A3.
Webworld: A Quintesson tricks Cyclonus into commiting the mentally unstable Galvatron into the insane asylum planet of Torkulon in hopes that the Torkuli would be forced to lobotomise him seeing that they deduced that he was a lost cause (and a dangerously unpredictable wild card).
Nightmare Planet: A group of Quintessons kidnapped Daniel in order to bring his nightmares to life and use them to destroy the Autobots
The Quintesson Journal: The two fueding planets of Zetaxis and Lenark were discovered via a Quintesson journal that they were fighting a pointless war so that the Quintessons could profit through selling their weapons to the two planets
Big Broadcast of 2006: Whilst in pursuit of the journal the Quintessons discover it was last seen on Junkion so they decide to brainwash the Junkions via subliminal messaging so that they can get them to uncover the journal for them. This plan eventually goes haywire after Autobot intervention
Dweller in the Depths: An age old aborted Quintesson experiment is released, a techno organic energy siphon used to drain energy from any living target and transforming them into Energy Vampires.
no subject
First introduced in the Movie and appeared in various Transformers episodes during Season 3 and were revealed (in the cartoon canon) to be the creators of all the Transformers on Cybertron.
They're basically tentacled beings with energy beams underneath usually seen with 5 faces (with some exceptions in episodes "The Killing Jar", "Dweller in the Depths" and "Madman's Paradise") which were later revealed to be the faces of:
Death (the most common one "We sentence Judge Deliberata to death" FFoD prt 2)
Wrath (Devil, "I praise your decision. Open the pit." FFoD prt 2)
Bitterness (solemn, green and teal face "Indeed, such intuitive powers could present a serious impediment to our operation." FFoD prt 2)
Doubt (pointier green helmet, "Erh, then recovering the journal will be more difficult than we'd imagined." Big Broadcast of 2006)
Laughter (orange seemingly the most benign dude, "It *About the supposed destruction of the Autobots* is a day so long in coming that I am uncertain how to celebrate it." - FFoD prt 3)
Some of their nefarious deeds in the animated series were:
Five Faces of Darkness: Revealed to be the creators of all the Transformers, tricked Galvatron into an alliance with the promise of a fictious Decepticon Matrix, interrogated Kup, Magnus and Spike about Cybertron before sending them to their deaths (they were saved by Arcee, Grimlock, Springer, Rodimus Prime and the Aerialbots) and then nearly destroyed them all by having the Sharkticons (in fact the deranged Galvatron was the one who activated the switch) activating a switch that made all Transformers inert (Spike saved them all)
The Killing Jar: A Quintesson named Inquirata (who is a single faced Quintesson) captured Ultra Magnus, Cyclonus, Marissa Faireborn and Wreck Gar in order to conduct behavoural experiments on them
Dark Awakening: Reviving Optimus Prime as a zombie to lure the Autobots into a trap that nearly succeeded
Madman's Paradise: A rogue Quintesson named Mara-Al-Utha conquered the magical realm of Menonia for millions of years (we are given insight into how the Quintessons dealt with law breakers of their spieces, namely by transporting them into other dimensions)
Forever is a Long Time Coming: Inquirata returns and his plan was to use a time window to kidnap the Autobot leader of the rebellion (that occured over millions of years ago) that drove the Quintessons from Cybertron, A3.
Webworld: A Quintesson tricks Cyclonus into commiting the mentally unstable Galvatron into the insane asylum planet of Torkulon in hopes that the Torkuli would be forced to lobotomise him seeing that they deduced that he was a lost cause (and a dangerously unpredictable wild card).
Nightmare Planet: A group of Quintessons kidnapped Daniel in order to bring his nightmares to life and use them to destroy the Autobots
The Quintesson Journal: The two fueding planets of Zetaxis and Lenark were discovered via a Quintesson journal that they were fighting a pointless war so that the Quintessons could profit through selling their weapons to the two planets
Big Broadcast of 2006: Whilst in pursuit of the journal the Quintessons discover it was last seen on Junkion so they decide to brainwash the Junkions via subliminal messaging so that they can get them to uncover the journal for them. This plan eventually goes haywire after Autobot intervention
Dweller in the Depths: An age old aborted Quintesson experiment is released, a techno organic energy siphon used to drain energy from any living target and transforming them into Energy Vampires.