Phase Sixer

When Megatron finalized the phased infiltration process, he selected three of his Warriors Elite to become Phase Sixers. These ultra-powerful 'bots would unleash their destructive powers on worlds that were on the brink of collapse, ravaging them utterly so they could be stripped of resources by the Decepticons.
The three known Phase Six Decepticons are:
Fiction
2005 IDW continuity
While Overlord was fighting a campaign on the world of Caldoon 4, Megatron summoned him to a tele-conference, announcing to him, Sixshot and Black Shadow that they would be his Phase Sixers. Overlord questioned the plan, refused his orders, and deserted from the Decepticon army, apparently for the sole reason of coercing Megatron to pursue him. This completely and totally failed. He went on to take over Garrus-9 in another attempt to gain Megatron's attention, his reign so sadistic that even the Decepticons under his control were desperate to escape, but the only attention he eventually gained was that of the Wreckers. Last Stand of the Wreckers
Sixshot and Black Shadow would go on to perform their duties for many years and came to be feared names among the Autobots.
Among Black Shadow's known battles were his destruction of Rigel IV and its 3 billion inhabitants, a battle with the Wreckers during which he killed three of them and dismembered their leader Hyperion; and his massacre of 3,003 members of the Autobots' 113th Battalion, an encounter that saw him personally best Optimus Prime and Ultra Magnus. Black Shadow's undoing came when he accepted half a billion Shanix from the Autobots in exchange for blowing up the Decepticons' fleet of War Worlds. The Decepticon Justice Division captured, tortured and executed him for the betrayal. Rules of Disengagement
Sixshot, meanwhile, had many battles of his own, but faced a lonely life as he was feared by foe and comrade alike. On the planet Mumu-Obscura, Sixshot was tempted by an offer to leave the Decepticons and join the Reapers, Spotlight: Sixshot an offer that would later be repeated on the planet Earth. Sixshot finally agreed–only to be immediately shut down by Starscream using the verbal "off switch" built into him. Devastation #5 Sixshot's body was recovered by Galvatron Devastation #6 and used by the Dead Universe scientist Jhiaxus as part of his plans for the Expansion. Spotlight: Doubledealer Freed of Jhiaxus's control following the defeat of the Dead Universe crew, Sixshot traded the scientist's technology to Megatron in exchange for his freedom from Phase Sixer duties. Spotlight: Metroplex
After the war, Prowl had a secret plan to pick apart a captured Overlord and find a way they could make Autobot Phase Sixers in case of trouble. Remembrance Day
Notes
- In one of the more egregious examples of their odd re-writing of dialogue to incorporate modern Transformers terminology, Shout! Factory's subtitles for the company's DVD release of the Transformers: The Headmasters cartoon has Sixshot identify himself as a "Phase Six Decepticon officer" in "Four Warriors Come out of the Sky". This, of course, makes basically no sense, since the infiltration protocol does not exist in Japanese cartoon continuity; in the actual Japanese dialogue, Sixshot refers to himself as a "Destron Dinobase Ninja Staff Officer".
- When asked on Twitter James Roberts has described Killmaster, Heretech[1] and Tarn[2] as Phase Sixers. However, given the context, it seems very likely that he was using "Phase Sixer" in the colloquial sense of "ununtrium-enhanced superwarrior", rather than the specific role of planet-destroyers that Sixshot, Black Shadow and Overlord were selected for. Although apparently Tarn has not been ununtrinium enhanced—Overlord used up the last ununtrinium in the universe, and the scene depicting Tarn's reconstruction does not share any similarities with that of Overlord's. Later stories wouild establish that his bursts of enormous power were due to the effects of dosing up on a special nucleon which made it's user extremely powerful in short bursts. Without it, he seems on par with a typical Point One Percenter.
- There are a couple of suggestions that there have been other Phase Sixers before the three named above—at least one of whom met their end at the hands of the Decepticon Justice Division. In a conversation on Garrus 9, Shockwave informs Overlord, "You're not the first phase-sixer to bait Megatron". And later on, when Tarn ends Black Shadow's life, he first laments Phase Sixers' "tedious tendency to rebel" and then shortly afterwards tells his team, "Stand back, everyone. Phase Sixers have a tendency to -" just as Black Shadow goes VOMF. If he hadn't taken a Phase Sixer down before, how could Tarn know what would happen?
Foreign Names
Swedish: Slutstegsutplånare ("Final Stage Exterminators")

