NOTE: THIS HAS NOT BEEN TESTED YET

This kit is made for making a custom Gilthor/Guiltar from Earthrise Optimus, with Siege/Earthrise Megatron's legs attached.

HOW TO PUT TOGETHER
You will need a screwdriver, Earthrise Prime, a Siege Megatron mold, a gun from the ER Cliffjumper mold, the minigun from Siege Astrotrain, and a missile from Siege Skyfire. You can swap the weapons out for whatever you like, or for 3D printed equivalents.
Open Optimus' gas canisters, and unscrew the screws inside. Once you get them undone, you can remove the legs, and leave them for whatever you want. Then, pop Megatron's legs off their mushroom pegs, and attach them to Prime. Prime's mushroom pegs are a tiny bit wider than Megatron's, so you may want to sand them down until they fit.
Take the revolver cylinder, and slide it onto the left arm, then attach Cliffjumper's gun. Skyfire's missile goes on the right arm, and the minigun goes on the back. Then, take the Shoulder pads, and slot them on. The exhaust pipes, if you haven't removed them, should fit into the slots in the pads. Then, attach the null rays to the tops of the pads.
If you haven't already painted, go ahead and to that now.
Behold! You very own Guiltar! There is a bit of Jank to the situation, like the thighs on Megatron have a small gap between them and Prime's hips, and the exhaust pipes may have a bit of trouble getting into place. Once done, you can still transform the figure! It's the standard Earthrise Prime conversion, but with Tank legs. You may notice that the truck cab is slanted downward, which you may not like. You can try to fix this, or settle for a mildly menacing angle on the truck.
If you so choose, you can sand the peg on top of the minigun down, until it fits on the Cliffjumper gun, so you can have the ability to combine all the weapons into one.
You may notice that one of the cylinders on the Revolver portion has a 5mm peg, rather than a port. This is so it can plug into the back of the Cliffjumper gun. When the weapons are combined, there is an adapter to allow for the attachment of the weapon to the vehicle mode like in the magazine.

FILES I USED
https://www.thingiverse.com/thing:4737848 for the Arm Cylinder
https://cults3d.com/en/3d-model/game/coronation-set-for-wfc-earthrise-starscream for the Shoulder Pads
https://cults3d.com/en/3d-model/game/articulated-jet-squad-no-support for the Null Rays