Be creative here there are no wrong ideas.
I would like the Spartan laser to be a weapon personally, just called something different "Charge Rifle" was a name I had in mind
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The left hand of destiny The right hand of fate Pistol set unique perk, when holding the left hand of destiny, allows the wielder to also hold the right hand of fate. Vice versa if you have the other hand cannon. Don't know about stats or perks but I imagine something cool could be thought up.