Hi Mitch,
Yes, that was the intent with this token. The Crit multiplier becomes x3 when a Rogue is wearing Nightshade's Grim Gloves, while making a melee Sneak Attack. Since Nightshade's Short Sword and Nightshade's Throwing Dagger both allow the Sneak Attack damage (+15 at 4th level, or +20 at 5th) to be included in the Crit, it would allow this number to be tripled instead of merely doubled on a Critical hit, once per combat.
It was discussed during Token Development that year, and I was paying a *lot* of attention to that discussion.
Some quick notes (which you seem to have caught correctly) that I've noticed some players - and occasionally DMs - are confused about:
* The x3 multiplier only works in Melee, not in Ranged... even if you're using the Throwing dagger which allows a Ranged Sneak Attack.
* The x3 is only for Sneak Attacks - not just any Melee Critical made by a Rogue.
* It only works once/combat, even if you have something (like the Necklace of the Sneak) which allows you to make multiple Sneak Attacks per combat.
* If you have an item which expands the Critical range (Necklace of the Sneak, Raphiel's Necklace, Amulet of Aiming, etc) then this effect DOES work on the expanded critical range, not just on a natural 20!
* You have to be able to actually Crit the monster - if it is immune to crits, or to Sneak Attacks, then this effect does nothing other than make you look cool. (So equip Bracers of Guided Strike or a Bead of Guided Strike, if possible!)
* Since the Viper Strike *set* bonus also allows Sneak Attack damage to be included in the Critical Multiplier, if a Rogue had at least 3 elements of: Viper Strike Pants, VS Shirt, VS Belt, or any Viper Strike Dagger in +2, +3 or +5 flavour... and was also wearing the Nightshade's Grim Gloves, the Sneak attack would also be x3 on a crit.
I highly encourage Rogues using the Grim Gloves to point out to their DM's that they qualify for triple damage, when their puck is in a Critical spot, because - and I say this as a DM - sometimes it's hard to track everything going on. Just be polite about it : )
- Raven (aka Nightshade)