A futuristic weapon wielded by Fagballs Shepard I’m not sure where he got it, but I assume it was from the museum of heroes. Certainly something like that would have been hard to miss in the school days of our past.
From limited observation it can be powered on and off. When idle the blade is cool but sharp. However, once turned on the edge glows and turns white hot, creating an incredibly dangerous and versatile weapon that can cut through nearly anything given time.
There is a crack running through it, whether his engineering skills are not yet at the level to fix it, or whether it is impossible I do not know. Regardless in the last 3 years it has yet to be broken and remains a steady companion of his person.