[quote=@SevenStormStyle]
If my character's weapon is not named in legend, do I make one up or just leave it without a name?
[/quote]

The first thing you should consider if their weapon isn't named, is if it's even worthy of being a Noble Phantasm in the first place.

Oh, you can just make up a name if it is. I expect it to be well thought out, though, no [i]"Raging Shadow Darkblade"[/i].