The Fortress Sinister is a Decepticon base built at the summit of a mountain in Oregon.
- (Note: The name "Fortress Sinister" is only found in the Marvel UK material. In Marvel US, it was referred to commonly as the "Decepticon fortress.")
Marvel Comics continuity
- (Note: Events from UK-only stories are in italics.)
Shortly after arriving on Earth the Decepticons attacked the Harrison Nuclear Power Plant and stripped it of useful technology. They then used the materials salvaged from the plant to build a giant fortress atop a nearby mountain.
Desperate for fuel they then kidnapped Sparkplug Witwicky and brought him to the fortress and attempted to force him into synthesising Transformer fuel from oil. Gears and the human superhero Spider-Man later infiltrated the fortress and managed to rescue Sparkplug. However Gears was sent plummeting to the ground and was badly damaged when Megatron blew a hole in the floor of the fortress.
Following Megatron’s disappearance and Shockwave sinking to the bottom of a swamp, Soundwave took command of the Decepticons and reoccupied the fortress. From here he coordinated a plan to destroy Optimus Prime by using a captured Bumblebee as bait.
Following Shockwave’s return he also returned to the fortress. During this period Buster Witwicky attempted to use an experimental robotic exosuit to infiltrate the fortress and show Optimus Prime that the suit was a good idea. He came face to face with Shockwave and narrowly escaped with his life.
Shockwave continued to use the fortress as a base, where he tested the newly developed Constructicons and eavesdropped on the premonitions granted to Buster by the Creation Matrix relating to the next generation of combiners.
After Megatron returned Soundwave managed to engineer a joint leadership between him and Shockwave which resulted in the fortress being abandoned for their long term base in the coal mine in Wyoming.
The fortress then remained unoccupied for many years until Shockwave once again used it following Ratbat’s assumption to the command of the main Decepticon force. Shockwave took the remaining Decepticons back the fortress.
It was here that he developed his plan to use Megatron as a weapon against Galvatron. Having brainwashed Megatron into a weapon he tested him against Cyclonus and Scourge after they revealed that they would be responsible for Shockwave’s death in the future. Megatron killed Cyclonus and Scourge barely escaped with his life.
This foreknowledge led Shockwave to have a breakdown and he mounted the body of Cyclonus on the wall as a trophy. Shockwave then descended into a depression and closeted himself away inside the fortress.
It was only when Ravage appealed to Shockwave’s logic that he left the fortress and cast the body of Cyclonus into a time rift that threatened reality. The fortress then played no further part in events and its fate remains unknown.