In robot mode, Optimus Prime splits into three components:
Although Optimus Prime can function as three independent modules, injury to any one module is felt by the other two.
Prime's original character description, as seen in the Transformers Universe comic and the series bible, named the robot module "Optimus" and the drone module "Prime", noting that the Prime module is also known as Roller. However, in practice, these names were never used. The robot module was always treated as if named "Optimus Prime", with "Prime" even being his most common nickname.
When Bumblebee and Sparkplug were caught by Decepticons, and with the clock ticking on the bomb they planted, Optimus Prime sent Roller into the mine. When the bomb exploded, Optimus was nearly destroyed, but Roller emerged cheekily unscathed, prompting Jazz to observe "Roller's one tough little Autobot!" ,
The Autobots were stuck in automotive mode by the evil Transfixatron. With Ironhide in the claws of Megatron's car-crushing machine, only Roller could save the day! Roller led the Decepticons on a merry chase, allowing Optimus to rescue Ironhide from the jaws of undignified death!
Marvel comics continuity
(Note: events from the Marvel UK comic are in italics.)
Optimus Prime used his Roller unit to command a battle in Washington, D.C. while actually sneaking away from the action to find Ravage. Kickback swooped in and destroyed Roller, causing Optimus Prime to double over in pain, and ironically saving him from the Insecticon Bombshell's cerebro-shell.
Spike's sally to sneakily sabotage the Solar Station was stymied by a sealed storage-door. Roller to the Rescue! Sent scuttling through the sage, secreted from Soundwave's sight, to supply a Cybertronian sonic multi-tool. Roller had saved the day!
Spike's subsequent sabotage of the solar station and ensuing detonation of the energon cubes in it could be construed (in some small way) to save the day as well.
IDW comics continuity
Roller was being considered for an exploring mission but lost out to Wheelie. Burn.
Megatron ordered Blitzwing to wait for Optimus Prime to come into range before firing on him. Optimus discreetly sent Roller ahead to intercept Blitzwing, and at the last moment, Roller blew him up good. Unfortunately, the same trick didn't work on Megatron, who buried the poor guy under a pile of rocks. However, this bought Optimus Prime the time to transfer his consciousness to his trailer section.
Roller is a small, cart-shaped device that Optimus Prime uses to slip unobtrusively behind enemy lines. He can maintain radio control over Roller at distances up to 1200 miles. Having Roller present somewhere is like being there himself.
Roller is a droid, able to function autonomously without Optimus's active oversight. But without Optimus, by far the most important of the three modules, Roller would not survive. Optimus shows great attachment and concern for Roller, who is left particularly vulnerable by the behind-the-scenes situations in which it specializes.
The bio information in the e-Hobby exclusive toy of Orion Pax established a pre-Earth history for Roller. Orion Pax was a transport and delivery worker on Cybertron. His body was composed of two autonomous units, Orion (the robot) and an industrial droid named Barrelroller, who transformed into an electromagnetic lift handle.
The name "Barrelroller" only appears in the official English-language translations of Orion Pax's bio on Takara's e-Hobby site. In the Japanese-language version of the bio—both online and on the pack-in bio card from the toy—Barrelroller is called simply "Roller". This more or less cements the idea that Barrelroller was rebuilt into Roller as we know him when Alpha Trion rebuilt Orion Pax into Optimus Prime.
- Optimus Prime (1984)
- Japanese ID number: C-01
- Roller was included with the original Optimus Prime toy (as well as its many rereleases). Roller is a small, six-wheeled vehicle that is stored in the trailer portion. The seats are scaled to allow Roller to carry Diaclone figures, due to its use in the prior toyline. The trailer/Combat Deck features a spring-loaded device that is capable of launching Roller out of the combat deck. Roller has a hole on top to hold the included oil pump or Optimus's gun.
Return of Convoy
- Star Convoy (Powered Master, 1991, 2005)
- Japanese ID number: C-372
- This toy from the Return of Convoy line included an upgraded Roller, patterned after a tracked ballistic missile carrier.
- Orion Pax (2006)
- Japanese ID number: 67
- This Japanese e-Hobby exclusive was a redeco of Targetmaster Recoil. As Orion Pax is meant to represent an early version of Optimus Prime, his Targetmaster partner, Barrelroller, is meant to represent an early version of Roller. This is the first version of Roller actually to transform, from robot to an electromagnetic lift handle.
- Optimus Prime (1993, 1994)
- A slightly altered version of the original Generation One Optimus Prime, it included Roller.
Smallest Transforming Transformers
- G1 Convoy Trailer (2003)
- Japanese ID Number: GTF-01B (trailer)
- The Combat Deck was available separately as a shortpacked figure. Included was a tiiiiny Roller. Aww!
- In wave 2.5, it was again available in cartoon colors as a chase figure.
- G1 Convoy (2006)
- Japanese ID number: THS-02
- THS-02 G1 Convoy is a finely detailed, partially die-cast metal transforming toy of G1 Optimus Prime. It comes with a fully transforming and highly detailed trailer that opens up into its Combat Deck/repair bay, as well as Roller, who features four-wheel steering.
- Roller is not part of the so-called Convoy Complete Edition (2006)
- Japanese ID number: MP-4
- The indignity!
- Optimus Prime 25th Anniversary Pack
- Roller is reissued with Optimus in blue as hasbro wants the unit to match Prime's fists. Origionaly it was intended to be grey.
- Roller is included with "anime" colors painted light gray (2008)
- Japanese ID number: 01
- When the Powermaster Optimus Prime toy was re-released as part of the Commemorative Series in 2003, included was Godbomber rechristened "Apex Bomber." In the on-package bio, Apex Bomber was described as a "roller drone" under Prime's control. This might have been intended to answer the question of what happened to Roller after Prime's Powermaster upgrade. However, Apex Bomber never appeared in any storylines (and Roller would reappear in Generation 2 anyway), so the issue is very much open for conjecture.
- Roller's characterization in the G1 animated series was very similar to R2-D2's (especially with the lack of dialogue), which goes hand in hand with a lot of the Star Wars parallels of the first series.