In Destiny 2: Shadowkeep, players can earn the new Moon armor and weapons by completing Essence quests that then allow them to craft specific gear at the Lectern of Enchantment. In order to earn the Love and Death grenade launcher, Destiny 2 players need to get the Bound Manacle weapon part on the Moon.
Unlike some of the other Essence quests where weapon parts were found lying around in different areas of the Moon map, the Bound Manacle item drops from defeating a specific enemy in the Gatehouse area of the Moon.
To get to the Gatehouse, head to the Hellmouth section of the map and then go to the east or the right side of the map. Enter into the Hellmouth interior along the path that players traveled in the Phogoth and Skolas Nightmare missions in Shadowkeep's campaign. The Gatehouse location will appear once players get down the stairs where the Hellmouth exterior is still visible, but continue on down the next set of stairs into the next big room that has the circular center. Go into the main part of this room to find a major Hive Knight named Ehrath-ur, Eternal Blade. Defeat this enemy to receive the Bound Manacle.
To see this path and the enemy players will need to defeat, here is a video from Ninja Pups:
The other part of the Love and Death's Essence of Insanity is to get 100 grenade launcher kills in strikes, Gambit, or the Crucible. The easiest and most efficient way to get this step done is to equip a grenade launcher in multiple slots and head into a strike to get this done. If players want they can get this done in Gambit or the Crucible if they are trying to get this done along with other bounties or objectives specific to those modes.
Love and Death is a heavy grenade launcher that goes in the power weapon slot. It is drum-fed and holds five rounds in the magazine. It is the same RPM as the popular Swarm of the Raven and can roll with Spike Grenades, as well as a new perk to Shadowkeep called Full Court that increases detonation damage as the projectile travels further before exploding.
Destiny 2: Shadowkeep is available now for PC, PS4, and Xbox One, with a Stadia version also in development.
Source: Ninja Pups