Seizer is a member of the ruling Triumverate who seized control of the Decepticons after the (second) death of Straxus. He is arrogant, lazy, and believes in a rather complacent method of Decepticon rule on Cybertron. He's the most violent of the three, but really only when someone dares bring him less than premium-grade oil.
Marvel UK comics continuity
An unspecified amount of time after the (second) death of Straxus, a triumvirate of Decepticons, ingeniously calling themselves the Triumverate, came to power as the new rulers of Cybertron. Legonis, Octus and Seizer ruled together from their palace at the city Helex, sharing a three-seater throne. Octus had the center seat.
As rulers of Cybertron the Triumverate were too lazy for active aggression against the Autobots. Instead they spent their time enjoying arena fights between Autobot prisoners and powerful Decepticon warriors (such as Quake), even contemplating pitting Decepticon against Decepticon should they run out of prisoners, rather than going out to get more.
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. Seizer realized they'd lost the crowd, and drew his gun to shoot Megatron in the back and re-affirm just who was in control. Realising that they hated not going out and killing Autobots, the Decepticons turned on the Triumverate for being lazy bozos.
- Octus (Octavius), Legonis (Lepidus) and Seizer (Caesar) were a parody of (or perhaps tribute to) the ruling Triumvirate of Rome after the death of Julius Caesar.
- Seizer's robot mode shows signs of him transforming into some kind of heavy mining machine.