Is there a standard stat block format for legendary items?

[Tinalles]

I'm generating stats for an NPC, and she has a legendary item. It's got a bunch of abilities. Is there a standard stat block format for the weapon itself?

[William Werminster]

Your imagination. If you feel lazy you can google for artifacts. Just be careful to not let your NPC become a 'Mary Sue'

[Tinalles]

Okay, thanks.

And yeah, I've worried about Mary Sue syndrome. The narrative setup calls for an unusually powerful NPC, and that's fertile ground for Mary Sues. I've taken measures to minimize her chance of upstaging the PCs.