During the House Of Wolves reveal of the Prison of Elders on May 6th, there was a new weapon used by Matt Simmons, one of the developers, and it seemed interesting enough to take a closer look. So this is a bit of an analysis about the weapon that was shown.
The weapon in question is a pistol called Vestian Dynasty. We only got a very brief look at the stat page for this weapon, but what we did see was that it isn't classified as a Hand Cannon like previous pistols in the game, but rather as a new class called Sidearm. Typically sidearm refers to the pistols law enforcement or military carry in addition to their primary weapon, which is usually a rifle. We can also see from the screen capture that it has Arc Damage. Commonly, elemental damage is reserved to secondary and heavy weapons with the exception of primary weapons from raids.
Vestian Dynasty appears to have maxed Rate of Fire, Stability and near perfect Reload. Which of these stats are augmented by the weapons mods are up for debate, but it seems to be a very accurate, low damage weapon. With a healthy magazine size of 15, the rate of fire should help in making up for the lack of impact on the weapon. Likely, there will be different barrels that increase the impact rate at the expense of other stats. Something else to keep in mind is that Legendary weapons that are acquired through random Legendary Engrams often come with different mods and perks, allowing for some pretty interesting versions of this weapon.
During the reveal, Matt Simmons used this pistol, and there were a few things we could gleam from those times when the focus was on him. As shown in the screen capture on the left, when using the Vestian Dynasty, he also has a primary weapon that has no element as well, as it's listed right below the pistol. Later on, he switched his primary to the Fang of Ir-Yut, but it appears that he still has the Vestian Dynasty equipped. This indicates that the Sidearm weapon class is a secondary weapon type. It's been brought up that he possibly swapped to the Fatebringer as it has arc damage as well, but Fatebringer is a primary weapon, so he would not have been able to equip the Fang of Ir-Yut as well.
Lastly, there was a moment during the reveal that may have indicated that the weapon comes from Dead Orbit, but it was a subtle comment made by one of the players, and the context is questionable as to why it was mentioned.