The Guillotine was originally designed in 2499 as a front line BattleMech. In time though it has been found that the Guillotine was more adept at raiding. The 'Mech was considered old near the end of the Star League but it was one of the most maneuverable 'Mechs that could be fielded and as such there was never any intention of stopping production of the design. As far as weapons most considered the Guillotine to be under gunned but the highly mobile nature of the 'Mech compensated for this lack of striking capabilities somewhat.
The Guillotine carries as its main weapon a Sunglow Large Laser. This is backed up with four ExoStar II Medium Lasers which gave the 'Mech a low dependence for the primary weapons. The final weapon on the design is a single Coventry-6 SRM 6. While the SRM alone is not threatening it gives the Guillotine a greater chance of scoring a critical strike on an enemy that has already taken damage. The SRM Ammunition is protected by a CASE system
- GLT-4L - The 4L Guillotine is a downgraded version of the original 4D Model. Due to the 4D models significant use of off the shelf technologies with the exception of the Endo Steel structure and CASE the 4L was a simple redesign using a standard internal structure and removal of the CASE. In order to do this the number of Heat Sinks were reduced by three.
- GLT-5M - The 5M model is a redesign that was performed after the Technological Renaissance that occurred in the late 3040s onward. The Large Laser has been upgraded to an ER model for extended reach. The 'Mech otherwise has an almost identical weapons configuration, speed profile and armor coverage as the 4D model.
- GLT-8T - The 8T variant picks up where the 5M left off. All of the Lasers have been upgraded to ER versions and the SRM 6 has been replaced with a Streak SRM 6 and an additional ER Large Laser has been added to the design. The Heat Sinks have been upgraded to Double Heat Sinks. Finally to make the design even deadlier then it was before a Targeting Computer has been added allowing the Guillotine to dispatch its foes with deadly accuracy.