After the (second) death ofStraxus, a coalition of leaders calling themselves theTriumvirate seized control of the Decepticons. Their rule was one of arrogant decadence, dominated bygladiatorial fights for their amusement rather than waging war upon the Autobots. Ultimately, their reign ended when they finally pushed the wrong Decepticons around.

What relation they have withDecepticon Imperial Headquarters,Decepticon High Command, or theDecepticon High Council is unknown.

Fiction

MarvelThe Transformers comics

Nothing bad can come of this, right?

An unspecified amount of time after the (second) death of Straxus, a triumvirate of Decepticons, ingeniously calling themselves the Triumverate,[sic] came to power as the new rulers ofCybertron.Legonis,Octus, andSeizer ruled together from their palace at the cityHelex, sharing a three-seater throne.

As rulers of Cybertron, the Triumverate were too lazy for active aggression against theAutobots. Instead, they spent their time enjoying arena fights between Autobot prisoners and powerful Decepticon warriors (such asQuake), even contemplating pitting Decepticon against Decepticon should they run out of prisoners, rather than going out to get more.

When Straxus-Megatron (it's complicated) arrived on Cybertron withRavage in tow, he was horrified with the state of things and challenged the Triumverate's rule. Octus baited Megatron, calling him the Decepticon cause's "most celebrated LOONY!"

Legonis shoved Megatron into the area (of the arena), where cannon-boy bashed up a few Decepticons (including Quake, the schmuck) before making a speech about Decepticon values. Realising that they hated not going out and killing Autobots, the Decepticons turned on the Triumverate for being lazy bozos.

TheTriggercons shot the Triumverate in the backs, killing them.The Fall and Rise of the Decepticon Empire.

Ask Sideways

When asked for the name of the Autobot known as "Big Red",Sideways mockedyou for wanting to know about stupid things and not wanting to know about more evil things such as the savagery ofGladiaron, the rule of the Triumvirate, or the world-devastating rampage ofMegazarak.Ask Sideways, 2015/07/04

Beast Wars: Uprising

During theGreat War, a triumvirate of warlords seizedHelex and governed it in Megatron's absence. They were eventually assassinated byPunch.Trigger Warnings

Notes

• In their original appearance, the Triumvirate was misspelled as "Triumverate". This article is titled using the proper spelling, which we got from the "Ask Sideways" incarnation ofAsk Vector Prime.
• Octus (Octavius), Legonis (Lepidus), and Seizer (Caesar) are a parody of (or perhaps tribute to) the rulingTriumvirate of Rome after the death ofJulius Caesar.