Arm Saber

First of all, huge credit to StrIntFire for the blade.

 

You can work out how it works and all the background details if you want, I don't have time right now.

 

The top one is a brace mounted saber used similarly to an upside down Guard Shoto and a brace made out of Mandalorean Iron, which means it's resistance to lightsabers.

 

With a few minor conversions you can change this arm mounted blade into a handheld one, where you can activate the precision cutter on the opposite end.

Done