With the 3.0 updates for Void, Arc, and Solar in Destiny 2, the keywords used by Stasis got added to the Light subclasses as well. Keywords are various buffs and debuffs that are unique to each sublcass and have a variety of effects. To further support all the new possible builds, weapons got new perks that allow players to apply these keywords to enemies.
While several Exotics got updated over the course of Year 5, Bungie added a new Exotic into the game with the launch of Witch Queen that worked well with Void 3.0. This Exotic is a Void Pulse Rifle called 
Collective Obligation.
How to Get Collective Obligation
In order to get Collective Obligation, Destiny 2 players will need to complete the Vow of the Disciple raid. This raid Exotic drops from the last boss, Rhulk. Bear in mind, however, that this is a random drop, and it may take some time for players to get it as it depends entirely on RNG. Some players may get extremely lucky and have it drop on the first completion, while others may get well over 50 clears and still not have this weapon yet.
Unlike Conditional Finality in Root of Nightmares, there is no way to increase the drop rate on Collective Obligation. The drop rate remains the same regardless of if Vow of the Disciple is completed on Normal or Master mode. Collective Obligation also does not have bad luck protection like 
Eyes of Tomorrow from Deep Stone Crypt does.
What Does Collective Obligation Do?
Collective Obligation has two perks unique to it. The first one is 
Void Leech. If a target damaged by this weapon has any of the Void debuffs on it (suppressed, weakened, and volatile), Collective Obligation will absorb those debuffs and begin to charge up. Once fully charged, players can press the reload button to switch the firing mode on Collective Obligation. This alternate firing mode activates a 15-second buff that applies any debuff that was absorbed by Collective Obligation to any target damaged by it.
So if a target had weakened and volatile on them when they were damaged by Collective Obligation, these debuffs will be reapplied to any target damaged by Collective Obligation when the Void Leech buff is active. As such, this causes Collective Obligation to work really well with many Void 3.0 builds for all classes.
Collective Obligation does not currently have a catalyst just like the rest of the raid Exotics (except for Vex Mythoclast and Touch of Malice). While a catalyst was data mined, it is not currently in the game, has no effect, and cannot be seen in-game like other catalysts. Since Bungie has been adding more catalysts to the game, it is possible that Collective Obligation may have a catalyst someday. If that happens, this guide will be updated accordingly.
Destiny 2 is available now on Epic Games Store, PS4, PS5, Steam, Xbox One, and Xbox Series X/S.